<van-index-bar>
 <van-index-anchor index="A" />
 <van-cell title="文本" />
 <van-cell title="文本" />
 <van-cell title="文本" />

 <van-index-anchor index="B" />
 <van-cell title="文本" />
 <van-cell title="文本" />
 <van-cell title="文本" />

 ...
</van-index-bar>

{
  "id": 101,
  "name": "北京市",
  "pid": 1,
  "code": 0
},
{
  "id": 10101,
  "name": "天津市",
  "pid": 10001,
  "code": 0
},
{
  "id": 20101,
  "name": "石家庄市",
  "pid": 20001,
  "code": 130100
}  

let cityNameList = []
for(let p in cityList){
  cityNameList.push(cityList[p].name)
}

npm install js-pinyin

import pinyin from 'js-pinyin'

let pinyin = require('js-pinyin')
pinyin.setOptions({checkPolyphone:false,charCase:0})

let firstName = {};
this.FirstPin.forEach((item)=>{
  firstName[item] = [];
  cityNameList.forEach((el)=>{
    let first = pinyin.getFullChars(el).substring(0,1);
    if( first == item ){
     firstName[item].push(el)
    }    
  })
 })

 FirstPin: ["A", "B", "C", "D", "E", "F", "G", "H", "J", "K", "L", "M", "N", "P", "Q", "R", "S", "T", "W", "X", "Y", "Z"],

firName:{
  A:["阿拉善盟","鞍山市"]
}

<van-index-bar class="indexBar" :sticky="false" highlight-color="#fb6463">
    <van-index-anchor  v-for="(item,index) in firstName" :key="index" :index="index">
     <span class="indexWord">{{index}}</span>
     <van-cell @click="chooseCity(citem)" v-for="(citem,cindex) in item" :key="cindex" :title="citem"/>
    </van-index-anchor>
 </van-index-bar>