element-plus/packages/components/form/src/utils.ts

import { computed, ref } from 'vue'
import { debugWarn, ensureArray } from '@element-plus/utils'
import type { Arrayable } from '@element-plus/utils'
import type { FormItemContext } from '@element-plus/tokens'
import type { FormItemProp } from './form-item'

const SCOPE = 'ElForm'

export function useFormLabelWidth() {
  const potentialLabelWidthArr = ref<number[]>([])

  const autoLabelWidth = computed(() => {
    if (!potentialLabelWidthArr.value.length) return '0'
    const max = Math.max(...potentialLabelWidthArr.value)
    return max ? `${max}px` : ''
  })

  function getLabelWidthIndex(width: number) {
    const index = potentialLabelWidthArr.value.indexOf(width)
    if (index === -1) {
      debugWarn(SCOPE, `unexpected width ${width}`)
    }
    return index
  }

  function registerLabelWidth(val: number, oldVal: number) {
    if (val && oldVal) {
      const index = getLabelWidthIndex(oldVal)
      potentialLabelWidthArr.value.splice(index, 1, val)
    } else if (val) {
      potentialLabelWidthArr.value.push(val)
    }
  }

  function deregisterLabelWidth(val: number) {
    const index = getLabelWidthIndex(val)
    if (index > -1) {
      potentialLabelWidthArr.value.splice(index, 1)
    }
  }

  return {
    autoLabelWidth,
    registerLabelWidth,
    deregisterLabelWidth,
  }
}

export const filterFields = (
  fields: FormItemContext[],
  props: Arrayable<FormItemProp>
) => {
  const normalized = ensureArray(props)
  return normalized.length > 0
    ? fields.filter((field) => field.prop && normalized.includes(field.prop))
    : fields
}