Element中的Cascader（級聯(lián)列表）動態(tài)加載省市\(zhòng)區(qū)數(shù)據(jù)的方法

var c={name: 'bob'}
var d=c
d.name = 'tom'
console.log(c)
// {name: "tom"}

var a = [
 {
 value: '2',
 children: [
 {
 value: '2-1',
 children: [
 {
 value: '2-1-1',
 children: [],
 },
 ],
 },
 {
 value: '2-2',
 children: [
 {
 value: '2-2-1',
 children: [],
 },
 {
 value: '2-2-2',
 children: [
 {
 value: '2-2-2-1',
 children: [],
 },
 ],
 },
 ],
 },
 ],
 },
]
var b = ['2','2-2','2-2-1']

a[0].children[1].children[0]

{
 value: '2-2-1',
 children: [],
 },

a[0].children[1].children[0].children = [{value: '2-2-1-1',children: []}]

console.log(a)

findRegionOption(regionOptions, regionArr) {
 if (_.isEmpty(regionArr) || _.isEmpty(regionOptions)) {
 return null
 }

 let regionId = _.first(regionArr)
 let regionOption = _.find(regionOptions, regionOption => {
 return regionOption.value === regionId
 })
 
 if (!regionOption) {
 return null
 }
 
 let tailRegionArr = _.tail(regionArr) // lodash的tail方法，獲取除了array數(shù)組第一個元素以外的全部元素。

 if (_.isEmpty(tailRegionArr)) {
 return regionOption
 }
 return this.findRegionOption(regionOption.children, tailRegionArr)
}

loadRegionChild(regionIdArr) {
 let regionOptions = this.regionHiera
 let regionOptionInUI = this.findRegionOption(regionOptions, regionIdArr)
 if (
 !regionOptionInUI ||
 !regionOptionInUI.children ||
 regionOptionInUI.children.length > 0
 ) {
 return null
 }

 let regionKey = _.last(regionIdArr)
 if (!regionKey) {
 return null
 }

 api
 .getRegionHiera(regionKey)
 .then(res => {
 let regionHiera = res.data
 regionOptionInUI.children = regionChildrenTransfomed // 動態(tài)加載賦值
 })
}

<template>
 <div>
 <el-cascader :options="regionHiera" v-model="selectedRegion" change-on-select/>
 </div>
</template>

<script>
export default {
 name: 'Test',
 data() {
 return {
 selectedRegion: [],
 regionHiera: [
 { label: 'Malaysia', value: '136', children: [] },
 { label: 'Indonesia', value: '106', children: [] },
 { label: '中華人民共和國', value: '100000', children: [] },
 { label: 'United States', value: '244', children: [] },
 ],
 }
 },
 watch: {
 selectedRegion(nv) {
 this.loadRegionChild(nv)
 },
 },
 methods: {
 findRegionOption(regionOptions, regionArr) {
 if (_.isEmpty(regionArr) || _.isEmpty(regionOptions)) {
 return null
 }

 let regionId = _.first(regionArr)
 let regionOption = _.find(regionOptions, regionOption => {
 return regionOption.value === regionId
 })
 if (!regionOption) {
 return null
 }
 let tailRegionArr = _.tail(regionArr)
 if (_.isEmpty(tailRegionArr)) {
 return regionOption
 }
 return this.findRegionOption(regionOption.children, tailRegionArr)
 },
 loadRegionChild(regionIdArr) {
 let regionOptions = this.regionHiera
 let regionOptionInUI = this.findRegionOption(regionOptions, regionIdArr)
 if (
 !regionOptionInUI ||
 !regionOptionInUI.children ||
 regionOptionInUI.children.length > 0
 ) {
 return null
 }

 let regionKey = _.last(regionIdArr)
 if (!regionKey) {
 return null
 }

 api
 .getRegionHiera(regionKey)
 .then(res => {
 let regionHiera = res.data //后臺返回數(shù)據(jù)
 regionOptionInUI.children = regionChildrenTransfomed
 })
 },
 }
}
</script>