From 5c4a3cb27b8d1e647c2eab22b4d75b0955c4ee50 Mon Sep 17 00:00:00 2001
From: Simona <36978416+SimonaliaChen@users.noreply.github.com>
Date: Fri, 25 Jun 2021 16:08:00 +0800
Subject: [PATCH] fix(cascader-panel): should not re-init when props's value
 not change (#2344)

* fix(cascader-panel): should not re-init when props's value not change

fix #2317 #1871

* style: extra space
---
 .../__tests__/cascader-panel.spec.ts          | 36 +++++++++++++++++++
 packages/cascader-panel/src/index.vue         |  7 +++-
 packages/utils/util.ts                        | 19 +++++++++-
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/packages/cascader-panel/__tests__/cascader-panel.spec.ts b/packages/cascader-panel/__tests__/cascader-panel.spec.ts
index 2a61fc638b..db7746162b 100644
--- a/packages/cascader-panel/__tests__/cascader-panel.spec.ts
+++ b/packages/cascader-panel/__tests__/cascader-panel.spec.ts
@@ -686,4 +686,40 @@ describe('CascaderPanel.vue', () => {
     await wrapper.setProps({ options: NORMAL_OPTIONS })
     expect(vm.getCheckedNodes(true).length).toBe(1)
   })
+
+  test('should not re-init when props\'s reference change but value not change', async () => {
+    const mockLazyLoad = jest.fn()
+    const wrapper = _mount({
+      template: `
+        <cascader-panel
+          v-model="value"
+          :props="props"
+        />
+      `,
+      data() {
+        return {
+          value: [],
+          props: {
+            lazy: true,
+            lazyLoad: mockLazyLoad,
+          },
+        }
+      },
+    })
+
+    await nextTick()
+    expect(mockLazyLoad).toBeCalled()
+
+    const sameMockLazyLoad = jest.fn()
+    wrapper.vm.props.lazyLoad = sameMockLazyLoad
+    await nextTick()
+    expect(sameMockLazyLoad).not.toBeCalled()
+
+    // should re-init when props's value change
+    const differentMockLazyLoad = jest.fn(lazyLoad)
+    wrapper.vm.props.lazyLoad = differentMockLazyLoad
+    await nextTick()
+    expect(differentMockLazyLoad).toBeCalled()
+  })
+
 })
diff --git a/packages/cascader-panel/src/index.vue b/packages/cascader-panel/src/index.vue
index b451ca099a..5c06d85e44 100644
--- a/packages/cascader-panel/src/index.vue
+++ b/packages/cascader-panel/src/index.vue
@@ -36,6 +36,7 @@ import {
   coerceTruthyValueToArray,
   deduplicate,
   isEmpty,
+  isEqualWithFunction,
 } from '@element-plus/utils/util'
 import { CommonProps, useCascaderConfig } from './config'
 import {
@@ -295,7 +296,11 @@ export default defineComponent({
 
     watch(
       [ config, () => props.options ],
-      initStore,
+      ([newConfig, newOptions], [oldConfig, oldOptions]) => {
+        if (isEqualWithFunction(newConfig, oldConfig) && isEqual(newOptions, oldOptions)) return
+
+        initStore()
+      },
       { deep: true, immediate: true },
     )
 
diff --git a/packages/utils/util.ts b/packages/utils/util.ts
index ae604af069..3284a30aeb 100644
--- a/packages/utils/util.ts
+++ b/packages/utils/util.ts
@@ -1,7 +1,9 @@
 import type { Ref } from 'vue'
 import { getCurrentInstance } from 'vue'
 
-import { camelize, capitalize, extend, hasOwn, hyphenate, isArray, isObject, isString, looseEqual, toRawType } from '@vue/shared'
+import { camelize, capitalize, extend, hasOwn, hyphenate, isArray, isObject, isString, isFunction, looseEqual, toRawType } from '@vue/shared'
+
+import isEqualWith from 'lodash/isEqualWith'
 
 import isServer from './isServer'
 import type { AnyFunction } from './types'
@@ -236,3 +238,18 @@ export function addUnit(value: string | number) {
   }
   return ''
 }
+
+/**
+ * Enhance `lodash.isEqual` for it always return false even two functions have completely same statements.
+ * @param obj The value to compare
+ * @param other The other value to compare
+ * @returns Returns `true` if the values are equivalent, else `false`.
+ * @example
+ *  lodash.isEqual(() => 1, () => 1)      // false
+ *  isEqualWith(() => 1, () => 1)         // true
+ */
+export function isEqualWithFunction (obj: any, other: any) {
+  return isEqualWith(obj, other, (objVal, otherVal) => {
+    return isFunction(objVal) && isFunction(otherVal) ? `${objVal}` === `${otherVal}` : undefined
+  })
+}