## Cascader

If the options have a clear hierarchical structure, Cascader can be used to view and select them.

### Basic usage

There are two ways to expand child option items.

:::demo Assigning the `options` attribute to an array of options renders a Cascader. The `props.expandTrigger` attribute defines how child options are expanded.
```html
<div class="block">
  <span class="demonstration">Child options expand when clicked (default)</span>
  <el-cascader
    v-model="value"
    :options="options"
    @change="handleChange"></el-cascader>
</div>
<div class="block">
  <span class="demonstration">Child options expand when hovered</span>
  <el-cascader
    v-model="value"
    :options="options"
    :props="{ expandTrigger: 'hover' }"
    @change="handleChange"></el-cascader>
</div>

<script>
  export default {
    data() {
      return {
        value: [],
        options: [{
          value: 'guide',
          label: 'Guide',
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      };
    },
    methods: {
      handleChange(value) {
        console.log(value);
      }
    }
  };
</script>

<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

  export default defineComponent({
    setup() {
      const state = reactive({
        value: [],
        options: [
          {
            value: 'guide',
            label: 'Guide',
            children: [
              {
                value: 'disciplines',
                label: 'Disciplines',
                children: [
                  {
                    value: 'consistency',
                    label: 'Consistency',
                  },
                  {
                    value: 'feedback',
                    label: 'Feedback',
                  },
                  {
                    value: 'efficiency',
                    label: 'Efficiency',
                  },
                  {
                    value: 'controllability',
                    label: 'Controllability',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'side nav',
                    label: 'Side Navigation',
                  },
                  {
                    value: 'top nav',
                    label: 'Top Navigation',
                  },
                ],
              },
            ],
          },
          {
            value: 'component',
            label: 'Component',
            children: [
              {
                value: 'basic',
                label: 'Basic',
                children: [
                  {
                    value: 'layout',
                    label: 'Layout',
                  },
                  {
                    value: 'color',
                    label: 'Color',
                  },
                  {
                    value: 'typography',
                    label: 'Typography',
                  },
                  {
                    value: 'icon',
                    label: 'Icon',
                  },
                  {
                    value: 'button',
                    label: 'Button',
                  },
                ],
              },
              {
                value: 'form',
                label: 'Form',
                children: [
                  {
                    value: 'radio',
                    label: 'Radio',
                  },
                  {
                    value: 'checkbox',
                    label: 'Checkbox',
                  },
                  {
                    value: 'input',
                    label: 'Input',
                  },
                  {
                    value: 'input-number',
                    label: 'InputNumber',
                  },
                  {
                    value: 'select',
                    label: 'Select',
                  },
                  {
                    value: 'cascader',
                    label: 'Cascader',
                  },
                  {
                    value: 'switch',
                    label: 'Switch',
                  },
                  {
                    value: 'slider',
                    label: 'Slider',
                  },
                  {
                    value: 'time-picker',
                    label: 'TimePicker',
                  },
                  {
                    value: 'date-picker',
                    label: 'DatePicker',
                  },
                  {
                    value: 'datetime-picker',
                    label: 'DateTimePicker',
                  },
                  {
                    value: 'upload',
                    label: 'Upload',
                  },
                  {
                    value: 'rate',
                    label: 'Rate',
                  },
                  {
                    value: 'form',
                    label: 'Form',
                  },
                ],
              },
              {
                value: 'data',
                label: 'Data',
                children: [
                  {
                    value: 'table',
                    label: 'Table',
                  },
                  {
                    value: 'tag',
                    label: 'Tag',
                  },
                  {
                    value: 'progress',
                    label: 'Progress',
                  },
                  {
                    value: 'tree',
                    label: 'Tree',
                  },
                  {
                    value: 'pagination',
                    label: 'Pagination',
                  },
                  {
                    value: 'badge',
                    label: 'Badge',
                  },
                ],
              },
              {
                value: 'notice',
                label: 'Notice',
                children: [
                  {
                    value: 'alert',
                    label: 'Alert',
                  },
                  {
                    value: 'loading',
                    label: 'Loading',
                  },
                  {
                    value: 'message',
                    label: 'Message',
                  },
                  {
                    value: 'message-box',
                    label: 'MessageBox',
                  },
                  {
                    value: 'notification',
                    label: 'Notification',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'menu',
                    label: 'NavMenu',
                  },
                  {
                    value: 'tabs',
                    label: 'Tabs',
                  },
                  {
                    value: 'breadcrumb',
                    label: 'Breadcrumb',
                  },
                  {
                    value: 'dropdown',
                    label: 'Dropdown',
                  },
                  {
                    value: 'steps',
                    label: 'Steps',
                  },
                ],
              },
              {
                value: 'others',
                label: 'Others',
                children: [
                  {
                    value: 'dialog',
                    label: 'Dialog',
                  },
                  {
                    value: 'tooltip',
                    label: 'Tooltip',
                  },
                  {
                    value: 'popover',
                    label: 'Popover',
                  },
                  {
                    value: 'card',
                    label: 'Card',
                  },
                  {
                    value: 'carousel',
                    label: 'Carousel',
                  },
                  {
                    value: 'collapse',
                    label: 'Collapse',
                  },
                ],
              },
            ],
          },
          {
            value: 'resource',
            label: 'Resource',
            children: [
              {
                value: 'axure',
                label: 'Axure Components',
              },
              {
                value: 'sketch',
                label: 'Sketch Templates',
              },
              {
                value: 'docs',
                label: 'Design Documentation',
              },
            ],
          },
        ],
      });
      const handleChange = (value) => {
        console.log(value);
      };
      return {
        ...toRefs(state),
        handleChange,
      };
    },
  });

</setup>
-->
```
:::

### Disabled option

Disable an option by setting a `disabled` field in the option object.

:::demo In this example, the first item in `options` array has a `disabled: true` field, so it is disabled. By default, Cascader checks the `disabled` field in each option object; if you are using another field name to indicate whether an option is disabled, you can assign it in the `props.disabled` attribute (see the API table below for details). And of course, field name `value`, `label` and `children` can also be customized in the same way.
```html
<el-cascader :options="options"></el-cascader>

<script>
  export default {
    data() {
      return {
        options: [{
          value: 'guide',
          label: 'Guide',
          disabled: true,
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      };
    }
  };
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

  export default defineComponent({
    setup() {
      const state = reactive({
        options: [
          {
            value: 'guide',
            label: 'Guide',
            disabled: true,
            children: [
              {
                value: 'disciplines',
                label: 'Disciplines',
                children: [
                  {
                    value: 'consistency',
                    label: 'Consistency',
                  },
                  {
                    value: 'feedback',
                    label: 'Feedback',
                  },
                  {
                    value: 'efficiency',
                    label: 'Efficiency',
                  },
                  {
                    value: 'controllability',
                    label: 'Controllability',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'side nav',
                    label: 'Side Navigation',
                  },
                  {
                    value: 'top nav',
                    label: 'Top Navigation',
                  },
                ],
              },
            ],
          },
          {
            value: 'component',
            label: 'Component',
            children: [
              {
                value: 'basic',
                label: 'Basic',
                children: [
                  {
                    value: 'layout',
                    label: 'Layout',
                  },
                  {
                    value: 'color',
                    label: 'Color',
                  },
                  {
                    value: 'typography',
                    label: 'Typography',
                  },
                  {
                    value: 'icon',
                    label: 'Icon',
                  },
                  {
                    value: 'button',
                    label: 'Button',
                  },
                ],
              },
              {
                value: 'form',
                label: 'Form',
                children: [
                  {
                    value: 'radio',
                    label: 'Radio',
                  },
                  {
                    value: 'checkbox',
                    label: 'Checkbox',
                  },
                  {
                    value: 'input',
                    label: 'Input',
                  },
                  {
                    value: 'input-number',
                    label: 'InputNumber',
                  },
                  {
                    value: 'select',
                    label: 'Select',
                  },
                  {
                    value: 'cascader',
                    label: 'Cascader',
                  },
                  {
                    value: 'switch',
                    label: 'Switch',
                  },
                  {
                    value: 'slider',
                    label: 'Slider',
                  },
                  {
                    value: 'time-picker',
                    label: 'TimePicker',
                  },
                  {
                    value: 'date-picker',
                    label: 'DatePicker',
                  },
                  {
                    value: 'datetime-picker',
                    label: 'DateTimePicker',
                  },
                  {
                    value: 'upload',
                    label: 'Upload',
                  },
                  {
                    value: 'rate',
                    label: 'Rate',
                  },
                  {
                    value: 'form',
                    label: 'Form',
                  },
                ],
              },
              {
                value: 'data',
                label: 'Data',
                children: [
                  {
                    value: 'table',
                    label: 'Table',
                  },
                  {
                    value: 'tag',
                    label: 'Tag',
                  },
                  {
                    value: 'progress',
                    label: 'Progress',
                  },
                  {
                    value: 'tree',
                    label: 'Tree',
                  },
                  {
                    value: 'pagination',
                    label: 'Pagination',
                  },
                  {
                    value: 'badge',
                    label: 'Badge',
                  },
                ],
              },
              {
                value: 'notice',
                label: 'Notice',
                children: [
                  {
                    value: 'alert',
                    label: 'Alert',
                  },
                  {
                    value: 'loading',
                    label: 'Loading',
                  },
                  {
                    value: 'message',
                    label: 'Message',
                  },
                  {
                    value: 'message-box',
                    label: 'MessageBox',
                  },
                  {
                    value: 'notification',
                    label: 'Notification',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'menu',
                    label: 'NavMenu',
                  },
                  {
                    value: 'tabs',
                    label: 'Tabs',
                  },
                  {
                    value: 'breadcrumb',
                    label: 'Breadcrumb',
                  },
                  {
                    value: 'dropdown',
                    label: 'Dropdown',
                  },
                  {
                    value: 'steps',
                    label: 'Steps',
                  },
                ],
              },
              {
                value: 'others',
                label: 'Others',
                children: [
                  {
                    value: 'dialog',
                    label: 'Dialog',
                  },
                  {
                    value: 'tooltip',
                    label: 'Tooltip',
                  },
                  {
                    value: 'popover',
                    label: 'Popover',
                  },
                  {
                    value: 'card',
                    label: 'Card',
                  },
                  {
                    value: 'carousel',
                    label: 'Carousel',
                  },
                  {
                    value: 'collapse',
                    label: 'Collapse',
                  },
                ],
              },
            ],
          },
          {
            value: 'resource',
            label: 'Resource',
            children: [
              {
                value: 'axure',
                label: 'Axure Components',
              },
              {
                value: 'sketch',
                label: 'Sketch Templates',
              },
              {
                value: 'docs',
                label: 'Design Documentation',
              },
            ],
          },
        ],
      });
      return {
        ...toRefs(state),
      };
    },
  });

</setup>
-->
```
:::

### Clearable

Set `clearable` attribute for `el-cascader` and a clear icon will appear when selected and hovered

:::demo
```html
<el-cascader :options="options" clearable></el-cascader>

<script>
  export default {
    data() {
      return {
        options: [{
          value: 'guide',
          label: 'Guide',
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      }
    }
  }
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

  export default defineComponent({
    setup() {
      const state = reactive({
        options: [
          {
            value: 'guide',
            label: 'Guide',
            children: [
              {
                value: 'disciplines',
                label: 'Disciplines',
                children: [
                  {
                    value: 'consistency',
                    label: 'Consistency',
                  },
                  {
                    value: 'feedback',
                    label: 'Feedback',
                  },
                  {
                    value: 'efficiency',
                    label: 'Efficiency',
                  },
                  {
                    value: 'controllability',
                    label: 'Controllability',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'side nav',
                    label: 'Side Navigation',
                  },
                  {
                    value: 'top nav',
                    label: 'Top Navigation',
                  },
                ],
              },
            ],
          },
          {
            value: 'component',
            label: 'Component',
            children: [
              {
                value: 'basic',
                label: 'Basic',
                children: [
                  {
                    value: 'layout',
                    label: 'Layout',
                  },
                  {
                    value: 'color',
                    label: 'Color',
                  },
                  {
                    value: 'typography',
                    label: 'Typography',
                  },
                  {
                    value: 'icon',
                    label: 'Icon',
                  },
                  {
                    value: 'button',
                    label: 'Button',
                  },
                ],
              },
              {
                value: 'form',
                label: 'Form',
                children: [
                  {
                    value: 'radio',
                    label: 'Radio',
                  },
                  {
                    value: 'checkbox',
                    label: 'Checkbox',
                  },
                  {
                    value: 'input',
                    label: 'Input',
                  },
                  {
                    value: 'input-number',
                    label: 'InputNumber',
                  },
                  {
                    value: 'select',
                    label: 'Select',
                  },
                  {
                    value: 'cascader',
                    label: 'Cascader',
                  },
                  {
                    value: 'switch',
                    label: 'Switch',
                  },
                  {
                    value: 'slider',
                    label: 'Slider',
                  },
                  {
                    value: 'time-picker',
                    label: 'TimePicker',
                  },
                  {
                    value: 'date-picker',
                    label: 'DatePicker',
                  },
                  {
                    value: 'datetime-picker',
                    label: 'DateTimePicker',
                  },
                  {
                    value: 'upload',
                    label: 'Upload',
                  },
                  {
                    value: 'rate',
                    label: 'Rate',
                  },
                  {
                    value: 'form',
                    label: 'Form',
                  },
                ],
              },
              {
                value: 'data',
                label: 'Data',
                children: [
                  {
                    value: 'table',
                    label: 'Table',
                  },
                  {
                    value: 'tag',
                    label: 'Tag',
                  },
                  {
                    value: 'progress',
                    label: 'Progress',
                  },
                  {
                    value: 'tree',
                    label: 'Tree',
                  },
                  {
                    value: 'pagination',
                    label: 'Pagination',
                  },
                  {
                    value: 'badge',
                    label: 'Badge',
                  },
                ],
              },
              {
                value: 'notice',
                label: 'Notice',
                children: [
                  {
                    value: 'alert',
                    label: 'Alert',
                  },
                  {
                    value: 'loading',
                    label: 'Loading',
                  },
                  {
                    value: 'message',
                    label: 'Message',
                  },
                  {
                    value: 'message-box',
                    label: 'MessageBox',
                  },
                  {
                    value: 'notification',
                    label: 'Notification',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'menu',
                    label: 'NavMenu',
                  },
                  {
                    value: 'tabs',
                    label: 'Tabs',
                  },
                  {
                    value: 'breadcrumb',
                    label: 'Breadcrumb',
                  },
                  {
                    value: 'dropdown',
                    label: 'Dropdown',
                  },
                  {
                    value: 'steps',
                    label: 'Steps',
                  },
                ],
              },
              {
                value: 'others',
                label: 'Others',
                children: [
                  {
                    value: 'dialog',
                    label: 'Dialog',
                  },
                  {
                    value: 'tooltip',
                    label: 'Tooltip',
                  },
                  {
                    value: 'popover',
                    label: 'Popover',
                  },
                  {
                    value: 'card',
                    label: 'Card',
                  },
                  {
                    value: 'carousel',
                    label: 'Carousel',
                  },
                  {
                    value: 'collapse',
                    label: 'Collapse',
                  },
                ],
              },
            ],
          },
          {
            value: 'resource',
            label: 'Resource',
            children: [
              {
                value: 'axure',
                label: 'Axure Components',
              },
              {
                value: 'sketch',
                label: 'Sketch Templates',
              },
              {
                value: 'docs',
                label: 'Design Documentation',
              },
            ],
          },
        ],
      });
      return {
        ...toRefs(state),
      };
    },
  });

</setup>
-->
```
:::

### Display only the last level

The input can display only the last level instead of all levels.

:::demo The `show-all-levels` attribute defines if all levels are displayed. If it is `false`, only the last level is displayed.
```html
<el-cascader :options="options" :show-all-levels="false"></el-cascader>
<script>
  export default {
    data() {
      return {
        options: [{
          value: 'guide',
          label: 'Guide',
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      };
    }
  };
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

export default defineComponent({
  setup() {
    const state = reactive({
      options: [
        {
          value: 'guide',
          label: 'Guide',
          children: [
            {
              value: 'disciplines',
              label: 'Disciplines',
              children: [
                {
                  value: 'consistency',
                  label: 'Consistency',
                },
                {
                  value: 'feedback',
                  label: 'Feedback',
                },
                {
                  value: 'efficiency',
                  label: 'Efficiency',
                },
                {
                  value: 'controllability',
                  label: 'Controllability',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'side nav',
                  label: 'Side Navigation',
                },
                {
                  value: 'top nav',
                  label: 'Top Navigation',
                },
              ],
            },
          ],
        },
        {
          value: 'component',
          label: 'Component',
          children: [
            {
              value: 'basic',
              label: 'Basic',
              children: [
                {
                  value: 'layout',
                  label: 'Layout',
                },
                {
                  value: 'color',
                  label: 'Color',
                },
                {
                  value: 'typography',
                  label: 'Typography',
                },
                {
                  value: 'icon',
                  label: 'Icon',
                },
                {
                  value: 'button',
                  label: 'Button',
                },
              ],
            },
            {
              value: 'form',
              label: 'Form',
              children: [
                {
                  value: 'radio',
                  label: 'Radio',
                },
                {
                  value: 'checkbox',
                  label: 'Checkbox',
                },
                {
                  value: 'input',
                  label: 'Input',
                },
                {
                  value: 'input-number',
                  label: 'InputNumber',
                },
                {
                  value: 'select',
                  label: 'Select',
                },
                {
                  value: 'cascader',
                  label: 'Cascader',
                },
                {
                  value: 'switch',
                  label: 'Switch',
                },
                {
                  value: 'slider',
                  label: 'Slider',
                },
                {
                  value: 'time-picker',
                  label: 'TimePicker',
                },
                {
                  value: 'date-picker',
                  label: 'DatePicker',
                },
                {
                  value: 'datetime-picker',
                  label: 'DateTimePicker',
                },
                {
                  value: 'upload',
                  label: 'Upload',
                },
                {
                  value: 'rate',
                  label: 'Rate',
                },
                {
                  value: 'form',
                  label: 'Form',
                },
              ],
            },
            {
              value: 'data',
              label: 'Data',
              children: [
                {
                  value: 'table',
                  label: 'Table',
                },
                {
                  value: 'tag',
                  label: 'Tag',
                },
                {
                  value: 'progress',
                  label: 'Progress',
                },
                {
                  value: 'tree',
                  label: 'Tree',
                },
                {
                  value: 'pagination',
                  label: 'Pagination',
                },
                {
                  value: 'badge',
                  label: 'Badge',
                },
              ],
            },
            {
              value: 'notice',
              label: 'Notice',
              children: [
                {
                  value: 'alert',
                  label: 'Alert',
                },
                {
                  value: 'loading',
                  label: 'Loading',
                },
                {
                  value: 'message',
                  label: 'Message',
                },
                {
                  value: 'message-box',
                  label: 'MessageBox',
                },
                {
                  value: 'notification',
                  label: 'Notification',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'menu',
                  label: 'NavMenu',
                },
                {
                  value: 'tabs',
                  label: 'Tabs',
                },
                {
                  value: 'breadcrumb',
                  label: 'Breadcrumb',
                },
                {
                  value: 'dropdown',
                  label: 'Dropdown',
                },
                {
                  value: 'steps',
                  label: 'Steps',
                },
              ],
            },
            {
              value: 'others',
              label: 'Others',
              children: [
                {
                  value: 'dialog',
                  label: 'Dialog',
                },
                {
                  value: 'tooltip',
                  label: 'Tooltip',
                },
                {
                  value: 'popover',
                  label: 'Popover',
                },
                {
                  value: 'card',
                  label: 'Card',
                },
                {
                  value: 'carousel',
                  label: 'Carousel',
                },
                {
                  value: 'collapse',
                  label: 'Collapse',
                },
              ],
            },
          ],
        },
        {
          value: 'resource',
          label: 'Resource',
          children: [
            {
              value: 'axure',
              label: 'Axure Components',
            },
            {
              value: 'sketch',
              label: 'Sketch Templates',
            },
            {
              value: 'docs',
              label: 'Design Documentation',
            },
          ],
        },
      ],
    });
    return {
      ...toRefs(state),
    };
  },
});

</setup>
-->
```
:::

### Multiple Selection

Set `props.multiple = true` to use multiple selection.

:::demo When using multiple selection, all selected tags will display by default, You can set `collapse-tags = true` to fold selected tags.
```html
<div class="block">
  <span class="demonstration">Display all tags (default)</span>
  <el-cascader
    :options="options"
    :props="props"
    clearable></el-cascader>
</div>
<div class="block">
  <span class="demonstration">Collapse tags</span>
  <el-cascader
    :options="options"
    :props="props"
    collapse-tags
    clearable></el-cascader>
</div>

<script>
  export default {
    data() {
      return {
        props: { multiple: true },
        options: [{
          value: 1,
          label: 'Asia',
          children: [{
            value: 2,
            label: 'China',
            children: [
              { value: 3, label: 'Beijing' },
              { value: 4, label: 'Shanghai' },
              { value: 5, label: 'Hangzhou' }
            ]
          }, {
            value: 6,
            label: 'Japan',
            children: [
              { value: 7, label: 'Tokyo' },
              { value: 8, label: 'Osaka' },
              { value: 9, label: 'Kyoto' }
            ]
          }, {
            value: 10,
            label: 'Korea',
            children: [
              { value: 11, label: 'Seoul' },
              { value: 12, label: 'Busan' },
              { value: 13, label: 'Taegu' }
            ]
          }]
        }, {
          value: 14,
          label: 'Europe',
          children: [{
            value: 15,
            label: 'France',
            children: [
              { value: 16, label: 'Paris' },
              { value: 17, label: 'Marseille' },
              { value: 18, label: 'Lyon' }
            ]
          }, {
            value: 19,
            label: 'UK',
            children: [
              { value: 20, label: 'London' },
              { value: 21, label: 'Birmingham' },
              { value: 22, label: 'Manchester' }
            ]
          }]
        }, {
          value: 23,
          label: 'North America',
          children: [{
            value: 24,
            label: 'US',
            children: [
              { value: 25, label: 'New York' },
              { value: 26, label: 'Los Angeles' },
              { value: 27, label: 'Washington' }
            ]
          }, {
            value: 28,
            label: 'Canada',
            children: [
              { value: 29, label: 'Toronto' },
              { value: 30, label: 'Montreal' },
              { value: 31, label: 'Ottawa' }
            ]
          }]
        }]
      };
    }
  };
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

export default defineComponent({
  setup() {
    const state = reactive({
      props: { multiple: true },
      options: [
        {
          value: 1,
          label: 'Asia',
          children: [
            {
              value: 2,
              label: 'China',
              children: [
                { value: 3, label: 'Beijing' },
                { value: 4, label: 'Shanghai' },
                { value: 5, label: 'Hangzhou' },
              ],
            },
            {
              value: 6,
              label: 'Japan',
              children: [
                { value: 7, label: 'Tokyo' },
                { value: 8, label: 'Osaka' },
                { value: 9, label: 'Kyoto' },
              ],
            },
            {
              value: 10,
              label: 'Korea',
              children: [
                { value: 11, label: 'Seoul' },
                { value: 12, label: 'Busan' },
                { value: 13, label: 'Taegu' },
              ],
            },
          ],
        },
        {
          value: 14,
          label: 'Europe',
          children: [
            {
              value: 15,
              label: 'France',
              children: [
                { value: 16, label: 'Paris' },
                { value: 17, label: 'Marseille' },
                { value: 18, label: 'Lyon' },
              ],
            },
            {
              value: 19,
              label: 'UK',
              children: [
                { value: 20, label: 'London' },
                { value: 21, label: 'Birmingham' },
                { value: 22, label: 'Manchester' },
              ],
            },
          ],
        },
        {
          value: 23,
          label: 'North America',
          children: [
            {
              value: 24,
              label: 'US',
              children: [
                { value: 25, label: 'New York' },
                { value: 26, label: 'Los Angeles' },
                { value: 27, label: 'Washington' },
              ],
            },
            {
              value: 28,
              label: 'Canada',
              children: [
                { value: 29, label: 'Toronto' },
                { value: 30, label: 'Montreal' },
                { value: 31, label: 'Ottawa' },
              ],
            },
          ],
        },
      ],
    });
    return {
      ...toRefs(state),
    };
  },
});

</setup>
-->
```
:::


### Select any level of options

In single selection, only the leaf nodes can be checked, and in multiple selection, check parent nodes will lead to leaf nodes be checked eventually. When enable this feature, it can make parent and child nodes unlinked and you can select any level of options.

:::demo Set `props.checkStrictly = true` to make checked state of a node not affects its parent nodes and child nodes, and then you can select any level of options.
```html
<div class="block">
  <span class="demonstration">Select any level of options (Single selection)</span>
  <el-cascader
    :options="options"
    :props="{ checkStrictly: true }"
    clearable></el-cascader>
</div>
<div class="block">
  <span class="demonstration">Select any level of options (Multiple selection)</span>
  <el-cascader
    :options="options"
    :props="{ multiple: true, checkStrictly: true }"
    clearable></el-cascader>
</div>

<script>
  export default {
    data() {
      return {
        options: [{
          value: 'guide',
          label: 'Guide',
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      };
    }
  };
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

export default defineComponent({
  setup() {
    const state = reactive({
      options: [
        {
          value: 'guide',
          label: 'Guide',
          children: [
            {
              value: 'disciplines',
              label: 'Disciplines',
              children: [
                {
                  value: 'consistency',
                  label: 'Consistency',
                },
                {
                  value: 'feedback',
                  label: 'Feedback',
                },
                {
                  value: 'efficiency',
                  label: 'Efficiency',
                },
                {
                  value: 'controllability',
                  label: 'Controllability',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'side nav',
                  label: 'Side Navigation',
                },
                {
                  value: 'top nav',
                  label: 'Top Navigation',
                },
              ],
            },
          ],
        },
        {
          value: 'component',
          label: 'Component',
          children: [
            {
              value: 'basic',
              label: 'Basic',
              children: [
                {
                  value: 'layout',
                  label: 'Layout',
                },
                {
                  value: 'color',
                  label: 'Color',
                },
                {
                  value: 'typography',
                  label: 'Typography',
                },
                {
                  value: 'icon',
                  label: 'Icon',
                },
                {
                  value: 'button',
                  label: 'Button',
                },
              ],
            },
            {
              value: 'form',
              label: 'Form',
              children: [
                {
                  value: 'radio',
                  label: 'Radio',
                },
                {
                  value: 'checkbox',
                  label: 'Checkbox',
                },
                {
                  value: 'input',
                  label: 'Input',
                },
                {
                  value: 'input-number',
                  label: 'InputNumber',
                },
                {
                  value: 'select',
                  label: 'Select',
                },
                {
                  value: 'cascader',
                  label: 'Cascader',
                },
                {
                  value: 'switch',
                  label: 'Switch',
                },
                {
                  value: 'slider',
                  label: 'Slider',
                },
                {
                  value: 'time-picker',
                  label: 'TimePicker',
                },
                {
                  value: 'date-picker',
                  label: 'DatePicker',
                },
                {
                  value: 'datetime-picker',
                  label: 'DateTimePicker',
                },
                {
                  value: 'upload',
                  label: 'Upload',
                },
                {
                  value: 'rate',
                  label: 'Rate',
                },
                {
                  value: 'form',
                  label: 'Form',
                },
              ],
            },
            {
              value: 'data',
              label: 'Data',
              children: [
                {
                  value: 'table',
                  label: 'Table',
                },
                {
                  value: 'tag',
                  label: 'Tag',
                },
                {
                  value: 'progress',
                  label: 'Progress',
                },
                {
                  value: 'tree',
                  label: 'Tree',
                },
                {
                  value: 'pagination',
                  label: 'Pagination',
                },
                {
                  value: 'badge',
                  label: 'Badge',
                },
              ],
            },
            {
              value: 'notice',
              label: 'Notice',
              children: [
                {
                  value: 'alert',
                  label: 'Alert',
                },
                {
                  value: 'loading',
                  label: 'Loading',
                },
                {
                  value: 'message',
                  label: 'Message',
                },
                {
                  value: 'message-box',
                  label: 'MessageBox',
                },
                {
                  value: 'notification',
                  label: 'Notification',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'menu',
                  label: 'NavMenu',
                },
                {
                  value: 'tabs',
                  label: 'Tabs',
                },
                {
                  value: 'breadcrumb',
                  label: 'Breadcrumb',
                },
                {
                  value: 'dropdown',
                  label: 'Dropdown',
                },
                {
                  value: 'steps',
                  label: 'Steps',
                },
              ],
            },
            {
              value: 'others',
              label: 'Others',
              children: [
                {
                  value: 'dialog',
                  label: 'Dialog',
                },
                {
                  value: 'tooltip',
                  label: 'Tooltip',
                },
                {
                  value: 'popover',
                  label: 'Popover',
                },
                {
                  value: 'card',
                  label: 'Card',
                },
                {
                  value: 'carousel',
                  label: 'Carousel',
                },
                {
                  value: 'collapse',
                  label: 'Collapse',
                },
              ],
            },
          ],
        },
        {
          value: 'resource',
          label: 'Resource',
          children: [
            {
              value: 'axure',
              label: 'Axure Components',
            },
            {
              value: 'sketch',
              label: 'Sketch Templates',
            },
            {
              value: 'docs',
              label: 'Design Documentation',
            },
          ],
        },
      ],
    });
    return {
      ...toRefs(state),
    };
  },
});

</setup>
-->
```
:::

### Dynamic loading

Dynamic load its child nodes when checked a node.

:::demo Set `lazy = true` to use dynamic loading, and you have to specify how to load the data source by `lazyload`. There are two parameters of `lazyload`,the first parameter `node` is the node currently clicked, and the `resolve` is a callback that indicate loading is finished which must invoke. To display the status of node more accurately, you can add a `leaf` field (can be modified by `props.leaf`) to indicate whether it is a leaf node. Otherwise, it will be inferred by if has any child nodes.
```html
<el-cascader :props="props"></el-cascader>

<script>
  let id = 0;

  export default {
    data() {
      return {
        props: {
          lazy: true,
          lazyLoad (node, resolve) {
            const { level } = node;
            setTimeout(() => {
              const nodes = Array.from({ length: level + 1 })
                .map(item => ({
                  value: ++id,
                  label: `Option - ${id}`,
                  leaf: level >= 2
                }));
              // Invoke `resolve` callback to return the child nodes data and indicate the loading is finished.
              resolve(nodes);
            }, 1000);
          }
        }
      };
    }
  };
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

let id = 0;

export default defineComponent({
  setup() {
    const state = reactive({
      props: {
        lazy: true,
        lazyLoad(node, resolve) {
          const { level } = node;
          setTimeout(() => {
            const nodes = Array.from({ length: level + 1 }).map((item) => ({
              value: ++id,
              label: `Option - ${id}`,
              leaf: level >= 2,
            }));
            // Invoke `resolve` callback to return the child nodes data and indicate the loading is finished.
            resolve(nodes);
          }, 1000);
        },
      },
    });
    return {
      ...toRefs(state),
    };
  },
});

</setup>
-->
```
:::

### Filterable

Search and select options with a keyword.

:::demo Adding `filterable` to `el-cascader` enables filtering. Cascader will match nodes whose label or parent's label (according to `show-all-levels`) includes input keyword. Of course, you can customize search logic by `filter-method` which accepts a function, the first parameter is `node`, the second is `keyword`, and need return a boolean value indicating whether it hits.
```html
<div class="block">
  <span class="demonstration">Filterable (Single selection)</span>
  <el-cascader
    placeholder="Try searchingL Guide"
    :options="options"
    filterable></el-cascader>
</div>
<div class="block">
  <span class="demonstration">Filterable (Multiple selection)</span>
  <el-cascader
    placeholder="Try searchingL Guide"
    :options="options"
    :props="{ multiple: true }"
    filterable></el-cascader>
</div>

<script>
  export default {
    data() {
      return {
        options: [{
          value: 'guide',
          label: 'Guide',
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      };
    }
  };
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

export default defineComponent({
  setup() {
    const state = reactive({
      options: [
        {
          value: 'guide',
          label: 'Guide',
          children: [
            {
              value: 'disciplines',
              label: 'Disciplines',
              children: [
                {
                  value: 'consistency',
                  label: 'Consistency',
                },
                {
                  value: 'feedback',
                  label: 'Feedback',
                },
                {
                  value: 'efficiency',
                  label: 'Efficiency',
                },
                {
                  value: 'controllability',
                  label: 'Controllability',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'side nav',
                  label: 'Side Navigation',
                },
                {
                  value: 'top nav',
                  label: 'Top Navigation',
                },
              ],
            },
          ],
        },
        {
          value: 'component',
          label: 'Component',
          children: [
            {
              value: 'basic',
              label: 'Basic',
              children: [
                {
                  value: 'layout',
                  label: 'Layout',
                },
                {
                  value: 'color',
                  label: 'Color',
                },
                {
                  value: 'typography',
                  label: 'Typography',
                },
                {
                  value: 'icon',
                  label: 'Icon',
                },
                {
                  value: 'button',
                  label: 'Button',
                },
              ],
            },
            {
              value: 'form',
              label: 'Form',
              children: [
                {
                  value: 'radio',
                  label: 'Radio',
                },
                {
                  value: 'checkbox',
                  label: 'Checkbox',
                },
                {
                  value: 'input',
                  label: 'Input',
                },
                {
                  value: 'input-number',
                  label: 'InputNumber',
                },
                {
                  value: 'select',
                  label: 'Select',
                },
                {
                  value: 'cascader',
                  label: 'Cascader',
                },
                {
                  value: 'switch',
                  label: 'Switch',
                },
                {
                  value: 'slider',
                  label: 'Slider',
                },
                {
                  value: 'time-picker',
                  label: 'TimePicker',
                },
                {
                  value: 'date-picker',
                  label: 'DatePicker',
                },
                {
                  value: 'datetime-picker',
                  label: 'DateTimePicker',
                },
                {
                  value: 'upload',
                  label: 'Upload',
                },
                {
                  value: 'rate',
                  label: 'Rate',
                },
                {
                  value: 'form',
                  label: 'Form',
                },
              ],
            },
            {
              value: 'data',
              label: 'Data',
              children: [
                {
                  value: 'table',
                  label: 'Table',
                },
                {
                  value: 'tag',
                  label: 'Tag',
                },
                {
                  value: 'progress',
                  label: 'Progress',
                },
                {
                  value: 'tree',
                  label: 'Tree',
                },
                {
                  value: 'pagination',
                  label: 'Pagination',
                },
                {
                  value: 'badge',
                  label: 'Badge',
                },
              ],
            },
            {
              value: 'notice',
              label: 'Notice',
              children: [
                {
                  value: 'alert',
                  label: 'Alert',
                },
                {
                  value: 'loading',
                  label: 'Loading',
                },
                {
                  value: 'message',
                  label: 'Message',
                },
                {
                  value: 'message-box',
                  label: 'MessageBox',
                },
                {
                  value: 'notification',
                  label: 'Notification',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'menu',
                  label: 'NavMenu',
                },
                {
                  value: 'tabs',
                  label: 'Tabs',
                },
                {
                  value: 'breadcrumb',
                  label: 'Breadcrumb',
                },
                {
                  value: 'dropdown',
                  label: 'Dropdown',
                },
                {
                  value: 'steps',
                  label: 'Steps',
                },
              ],
            },
            {
              value: 'others',
              label: 'Others',
              children: [
                {
                  value: 'dialog',
                  label: 'Dialog',
                },
                {
                  value: 'tooltip',
                  label: 'Tooltip',
                },
                {
                  value: 'popover',
                  label: 'Popover',
                },
                {
                  value: 'card',
                  label: 'Card',
                },
                {
                  value: 'carousel',
                  label: 'Carousel',
                },
                {
                  value: 'collapse',
                  label: 'Collapse',
                },
              ],
            },
          ],
        },
        {
          value: 'resource',
          label: 'Resource',
          children: [
            {
              value: 'axure',
              label: 'Axure Components',
            },
            {
              value: 'sketch',
              label: 'Sketch Templates',
            },
            {
              value: 'docs',
              label: 'Design Documentation',
            },
          ],
        },
      ],
    });
    return {
      ...toRefs(state),
    };
  },
});

</setup>
-->
```
:::

### Custom option content

You can customize the content of cascader node.

:::demo You can customize the content of cascader node by `scoped slot`. You'll have access to `node` and `data` in the scope,  standing for the Node object and node data of the current node respectively。
```html
<el-cascader :options="options">
  <template #default="{ node, data }">
    <span>{{ data.label }}</span>
    <span v-if="!node.isLeaf"> ({{ data.children.length }}) </span>
  </template>
</el-cascader>

<script>
  export default {
    data() {
      return {
        options: [{
          value: 'guide',
          label: 'Guide',
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      }
    }
  }
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

  export default defineComponent({
    setup() {
      const state = reactive({
        options: [
          {
            value: 'guide',
            label: 'Guide',
            children: [
              {
                value: 'disciplines',
                label: 'Disciplines',
                children: [
                  {
                    value: 'consistency',
                    label: 'Consistency',
                  },
                  {
                    value: 'feedback',
                    label: 'Feedback',
                  },
                  {
                    value: 'efficiency',
                    label: 'Efficiency',
                  },
                  {
                    value: 'controllability',
                    label: 'Controllability',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'side nav',
                    label: 'Side Navigation',
                  },
                  {
                    value: 'top nav',
                    label: 'Top Navigation',
                  },
                ],
              },
            ],
          },
          {
            value: 'component',
            label: 'Component',
            children: [
              {
                value: 'basic',
                label: 'Basic',
                children: [
                  {
                    value: 'layout',
                    label: 'Layout',
                  },
                  {
                    value: 'color',
                    label: 'Color',
                  },
                  {
                    value: 'typography',
                    label: 'Typography',
                  },
                  {
                    value: 'icon',
                    label: 'Icon',
                  },
                  {
                    value: 'button',
                    label: 'Button',
                  },
                ],
              },
              {
                value: 'form',
                label: 'Form',
                children: [
                  {
                    value: 'radio',
                    label: 'Radio',
                  },
                  {
                    value: 'checkbox',
                    label: 'Checkbox',
                  },
                  {
                    value: 'input',
                    label: 'Input',
                  },
                  {
                    value: 'input-number',
                    label: 'InputNumber',
                  },
                  {
                    value: 'select',
                    label: 'Select',
                  },
                  {
                    value: 'cascader',
                    label: 'Cascader',
                  },
                  {
                    value: 'switch',
                    label: 'Switch',
                  },
                  {
                    value: 'slider',
                    label: 'Slider',
                  },
                  {
                    value: 'time-picker',
                    label: 'TimePicker',
                  },
                  {
                    value: 'date-picker',
                    label: 'DatePicker',
                  },
                  {
                    value: 'datetime-picker',
                    label: 'DateTimePicker',
                  },
                  {
                    value: 'upload',
                    label: 'Upload',
                  },
                  {
                    value: 'rate',
                    label: 'Rate',
                  },
                  {
                    value: 'form',
                    label: 'Form',
                  },
                ],
              },
              {
                value: 'data',
                label: 'Data',
                children: [
                  {
                    value: 'table',
                    label: 'Table',
                  },
                  {
                    value: 'tag',
                    label: 'Tag',
                  },
                  {
                    value: 'progress',
                    label: 'Progress',
                  },
                  {
                    value: 'tree',
                    label: 'Tree',
                  },
                  {
                    value: 'pagination',
                    label: 'Pagination',
                  },
                  {
                    value: 'badge',
                    label: 'Badge',
                  },
                ],
              },
              {
                value: 'notice',
                label: 'Notice',
                children: [
                  {
                    value: 'alert',
                    label: 'Alert',
                  },
                  {
                    value: 'loading',
                    label: 'Loading',
                  },
                  {
                    value: 'message',
                    label: 'Message',
                  },
                  {
                    value: 'message-box',
                    label: 'MessageBox',
                  },
                  {
                    value: 'notification',
                    label: 'Notification',
                  },
                ],
              },
              {
                value: 'navigation',
                label: 'Navigation',
                children: [
                  {
                    value: 'menu',
                    label: 'NavMenu',
                  },
                  {
                    value: 'tabs',
                    label: 'Tabs',
                  },
                  {
                    value: 'breadcrumb',
                    label: 'Breadcrumb',
                  },
                  {
                    value: 'dropdown',
                    label: 'Dropdown',
                  },
                  {
                    value: 'steps',
                    label: 'Steps',
                  },
                ],
              },
              {
                value: 'others',
                label: 'Others',
                children: [
                  {
                    value: 'dialog',
                    label: 'Dialog',
                  },
                  {
                    value: 'tooltip',
                    label: 'Tooltip',
                  },
                  {
                    value: 'popover',
                    label: 'Popover',
                  },
                  {
                    value: 'card',
                    label: 'Card',
                  },
                  {
                    value: 'carousel',
                    label: 'Carousel',
                  },
                  {
                    value: 'collapse',
                    label: 'Collapse',
                  },
                ],
              },
            ],
          },
          {
            value: 'resource',
            label: 'Resource',
            children: [
              {
                value: 'axure',
                label: 'Axure Components',
              },
              {
                value: 'sketch',
                label: 'Sketch Templates',
              },
              {
                value: 'docs',
                label: 'Design Documentation',
              },
            ],
          },
        ],
      });
      return {
        ...toRefs(state),
      };
    },
  });

</setup>
-->
```
:::

### Cascader panel

`CascaderPanel` is the core component of `Cascader` which has various of features such as single selection, multiple selection, dynamic loading and so on.

:::demo Just like `el-cascader`, you can set alternative options by `options`, and enable other features by `props`, see the API form below for details.
```html
<el-cascader-panel :options="options"></el-cascader-panel>

<script>
  export default {
    data() {
      return {
        options: [{
          value: 'guide',
          label: 'Guide',
          children: [{
            value: 'disciplines',
            label: 'Disciplines',
            children: [{
              value: 'consistency',
              label: 'Consistency'
            }, {
              value: 'feedback',
              label: 'Feedback'
            }, {
              value: 'efficiency',
              label: 'Efficiency'
            }, {
              value: 'controllability',
              label: 'Controllability'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'side nav',
              label: 'Side Navigation'
            }, {
              value: 'top nav',
              label: 'Top Navigation'
            }]
          }]
        }, {
          value: 'component',
          label: 'Component',
          children: [{
            value: 'basic',
            label: 'Basic',
            children: [{
              value: 'layout',
              label: 'Layout'
            }, {
              value: 'color',
              label: 'Color'
            }, {
              value: 'typography',
              label: 'Typography'
            }, {
              value: 'icon',
              label: 'Icon'
            }, {
              value: 'button',
              label: 'Button'
            }]
          }, {
            value: 'form',
            label: 'Form',
            children: [{
              value: 'radio',
              label: 'Radio'
            }, {
              value: 'checkbox',
              label: 'Checkbox'
            }, {
              value: 'input',
              label: 'Input'
            }, {
              value: 'input-number',
              label: 'InputNumber'
            }, {
              value: 'select',
              label: 'Select'
            }, {
              value: 'cascader',
              label: 'Cascader'
            }, {
              value: 'switch',
              label: 'Switch'
            }, {
              value: 'slider',
              label: 'Slider'
            }, {
              value: 'time-picker',
              label: 'TimePicker'
            }, {
              value: 'date-picker',
              label: 'DatePicker'
            }, {
              value: 'datetime-picker',
              label: 'DateTimePicker'
            }, {
              value: 'upload',
              label: 'Upload'
            }, {
              value: 'rate',
              label: 'Rate'
            }, {
              value: 'form',
              label: 'Form'
            }]
          }, {
            value: 'data',
            label: 'Data',
            children: [{
              value: 'table',
              label: 'Table'
            }, {
              value: 'tag',
              label: 'Tag'
            }, {
              value: 'progress',
              label: 'Progress'
            }, {
              value: 'tree',
              label: 'Tree'
            }, {
              value: 'pagination',
              label: 'Pagination'
            }, {
              value: 'badge',
              label: 'Badge'
            }]
          }, {
            value: 'notice',
            label: 'Notice',
            children: [{
              value: 'alert',
              label: 'Alert'
            }, {
              value: 'loading',
              label: 'Loading'
            }, {
              value: 'message',
              label: 'Message'
            }, {
              value: 'message-box',
              label: 'MessageBox'
            }, {
              value: 'notification',
              label: 'Notification'
            }]
          }, {
            value: 'navigation',
            label: 'Navigation',
            children: [{
              value: 'menu',
              label: 'NavMenu'
            }, {
              value: 'tabs',
              label: 'Tabs'
            }, {
              value: 'breadcrumb',
              label: 'Breadcrumb'
            }, {
              value: 'dropdown',
              label: 'Dropdown'
            }, {
              value: 'steps',
              label: 'Steps'
            }]
          }, {
            value: 'others',
            label: 'Others',
            children: [{
              value: 'dialog',
              label: 'Dialog'
            }, {
              value: 'tooltip',
              label: 'Tooltip'
            }, {
              value: 'popover',
              label: 'Popover'
            }, {
              value: 'card',
              label: 'Card'
            }, {
              value: 'carousel',
              label: 'Carousel'
            }, {
              value: 'collapse',
              label: 'Collapse'
            }]
          }]
        }, {
          value: 'resource',
          label: 'Resource',
          children: [{
            value: 'axure',
            label: 'Axure Components'
          }, {
            value: 'sketch',
            label: 'Sketch Templates'
          }, {
            value: 'docs',
            label: 'Design Documentation'
          }]
        }]
      };
    }
  };
</script>
<!--
<setup>

import { defineComponent, reactive, toRefs } from 'vue';

export default defineComponent({
  setup() {
    const state = reactive({
      options: [
        {
          value: 'guide',
          label: 'Guide',
          children: [
            {
              value: 'disciplines',
              label: 'Disciplines',
              children: [
                {
                  value: 'consistency',
                  label: 'Consistency',
                },
                {
                  value: 'feedback',
                  label: 'Feedback',
                },
                {
                  value: 'efficiency',
                  label: 'Efficiency',
                },
                {
                  value: 'controllability',
                  label: 'Controllability',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'side nav',
                  label: 'Side Navigation',
                },
                {
                  value: 'top nav',
                  label: 'Top Navigation',
                },
              ],
            },
          ],
        },
        {
          value: 'component',
          label: 'Component',
          children: [
            {
              value: 'basic',
              label: 'Basic',
              children: [
                {
                  value: 'layout',
                  label: 'Layout',
                },
                {
                  value: 'color',
                  label: 'Color',
                },
                {
                  value: 'typography',
                  label: 'Typography',
                },
                {
                  value: 'icon',
                  label: 'Icon',
                },
                {
                  value: 'button',
                  label: 'Button',
                },
              ],
            },
            {
              value: 'form',
              label: 'Form',
              children: [
                {
                  value: 'radio',
                  label: 'Radio',
                },
                {
                  value: 'checkbox',
                  label: 'Checkbox',
                },
                {
                  value: 'input',
                  label: 'Input',
                },
                {
                  value: 'input-number',
                  label: 'InputNumber',
                },
                {
                  value: 'select',
                  label: 'Select',
                },
                {
                  value: 'cascader',
                  label: 'Cascader',
                },
                {
                  value: 'switch',
                  label: 'Switch',
                },
                {
                  value: 'slider',
                  label: 'Slider',
                },
                {
                  value: 'time-picker',
                  label: 'TimePicker',
                },
                {
                  value: 'date-picker',
                  label: 'DatePicker',
                },
                {
                  value: 'datetime-picker',
                  label: 'DateTimePicker',
                },
                {
                  value: 'upload',
                  label: 'Upload',
                },
                {
                  value: 'rate',
                  label: 'Rate',
                },
                {
                  value: 'form',
                  label: 'Form',
                },
              ],
            },
            {
              value: 'data',
              label: 'Data',
              children: [
                {
                  value: 'table',
                  label: 'Table',
                },
                {
                  value: 'tag',
                  label: 'Tag',
                },
                {
                  value: 'progress',
                  label: 'Progress',
                },
                {
                  value: 'tree',
                  label: 'Tree',
                },
                {
                  value: 'pagination',
                  label: 'Pagination',
                },
                {
                  value: 'badge',
                  label: 'Badge',
                },
              ],
            },
            {
              value: 'notice',
              label: 'Notice',
              children: [
                {
                  value: 'alert',
                  label: 'Alert',
                },
                {
                  value: 'loading',
                  label: 'Loading',
                },
                {
                  value: 'message',
                  label: 'Message',
                },
                {
                  value: 'message-box',
                  label: 'MessageBox',
                },
                {
                  value: 'notification',
                  label: 'Notification',
                },
              ],
            },
            {
              value: 'navigation',
              label: 'Navigation',
              children: [
                {
                  value: 'menu',
                  label: 'NavMenu',
                },
                {
                  value: 'tabs',
                  label: 'Tabs',
                },
                {
                  value: 'breadcrumb',
                  label: 'Breadcrumb',
                },
                {
                  value: 'dropdown',
                  label: 'Dropdown',
                },
                {
                  value: 'steps',
                  label: 'Steps',
                },
              ],
            },
            {
              value: 'others',
              label: 'Others',
              children: [
                {
                  value: 'dialog',
                  label: 'Dialog',
                },
                {
                  value: 'tooltip',
                  label: 'Tooltip',
                },
                {
                  value: 'popover',
                  label: 'Popover',
                },
                {
                  value: 'card',
                  label: 'Card',
                },
                {
                  value: 'carousel',
                  label: 'Carousel',
                },
                {
                  value: 'collapse',
                  label: 'Collapse',
                },
              ],
            },
          ],
        },
        {
          value: 'resource',
          label: 'Resource',
          children: [
            {
              value: 'axure',
              label: 'Axure Components',
            },
            {
              value: 'sketch',
              label: 'Sketch Templates',
            },
            {
              value: 'docs',
              label: 'Design Documentation',
            },
          ],
        },
      ],
    });
    return {
      ...toRefs(state),
    };
  },
});

</setup>
-->
```
:::

### Cascader Attributes
| Attribute | Description | Type  | Accepted Values | Default |
|---------- |-------- |---------- |-------------  |-------- |
| model-value / v-model | binding value | - | — | — |
| options | data of the options，the key of `value` and `label` can be customize by `Props`.| array | — | — |
| props | configuration options, see the following table. | object | — | — |
| size | size of input | string | medium / small / mini | — |
| placeholder | placeholder of input | string | — | Select |
| disabled | whether Cascader is disabled | boolean | — | false |
| clearable | whether selected value can be cleared | boolean | — | false |
| show-all-levels | whether to display all levels of the selected value in the input | boolean | — | true |
| collapse-tags | whether to collapse tags in multiple selection mode | boolean | - | false |
| separator | option label separator | string | — | ' / ' |
| filterable | whether the options can be searched | boolean | — | — |
| filter-method | customize search logic, the first parameter is `node`, the second is `keyword`, and need return a boolean value indicating whether it hits. | function(node, keyword) | - | - |
| debounce | debounce delay when typing filter keyword, in milliseconds | number | — | 300 |
| before-filter | hook function before filtering with the value to be filtered as its parameter. If `false` is returned or a `Promise` is returned and then is rejected, filtering will be aborted | function(value) | — | — |
| popper-class | custom class name for Cascader's dropdown   | string | —  | — |

### Cascader Events
| Event Name | Description | Parameters |
|---------- |-------- |---------- |
| change | triggers when the binding value changes | value |
| expand-change | triggers when expand option changes | an array of the expanding node's parent nodes |
| blur | triggers when Cascader blurs | (event: Event) |
| focus | triggers when Cascader focuses | (event: Event) |
| visible-change | triggers when the dropdown appears/disappears | true when it appears, and false otherwise |
| remove-tag | triggers when remove tag in multiple selection mode | the value of the tag which is removed |

### Cascader Methods
| Method Name | Description | Parameters |
| ---- | ---- | ---- |
| getCheckedNodes | get an array of currently selected node | (leafOnly) whether only return the leaf checked nodes, default is `false` |

### Cascader Slots
| Name | Description |
|---------|-------------|
| - | the custom content of cascader node, the parameter is { node, data }, which are current Node object and node data respectively. |
| empty  | content when there is no matched options. |

### CascaderPanel Attributes
| Attribute | Description | Type  | Accepted Values | Default |
|---------- |-------- |---------- |-------------  |-------- |
| model-value / v-model | binding value | - | — | — |
| options | data of the options，the key of `value` and `label` can be customize by `Props`.| array | — | — |
| props | configuration options, see the following table. | object | — | — |

### CascaderPanel Events
| Event Name | Description | Parameters |
|---------- |-------- |---------- |
| change | triggers when the binding value changes | value |
| expand-change | triggers when expand option changes | an array of the expanding node's parent nodes |

### CascaderPanel Methods
| Method Name | Description | Parameters |
| ---- | ---- | ---- |
| getCheckedNodes | get an array of currently selected node | (leafOnly) whether only return the leaf checked nodes, default is `false` |
| clearCheckedNodes | clear checked nodes | - |

### CascaderPanel Slots
| Name | Description |
|---------|-------------|
| - | the custom content of cascader node, the parameter is { node, data }, which are current Node object and node data respectively. |

### Props
| Attribute | Description | Type  | Accepted Values | Default |
| -------- | ----------------- | ------ | ------ | ------ |
| expandTrigger | trigger mode of expanding options | string | click / hover | 'click' |
| multiple | whether multiple selection is enabled | boolean | - | false |
| checkStrictly | whether checked state of a node not affects its parent and child nodes | boolean | - | false |
| emitPath | when checked nodes change, whether to emit an array of node's path, if false, only emit the value of node. | boolean | - | true |
| lazy | whether to dynamic load child nodes, use with `lazyload` attribute | boolean | - | false |
| lazyLoad | method for loading child nodes data, only works when `lazy` is true | function(node, resolve) | - | - |
| value    | specify which key of node object is used as the node's value | string | — | 'value' |
| label    | specify which key of node object is used as the node's label | string | — | 'label' |
| children | specify which key of node object is used as the node's children | string | — | 'children' |
| disabled | specify which key of node object is used as the node's disabled | string | — | 'disabled' |
| leaf     | specify which key of node object is used as the node's leaf field | string | — | 'leaf' |
