test.wpy

<template>
  <view class="container">
    {{obj.list.length}}
    {{objList.length}}
    {{objListLength}}
     /
    {{pureList.length}}
    {{pureListLength}}
     /
    {{listObj[0].list.length}}
    {{listObjList.length}}
    <button @tap="test">test</button>
  </view>
</template>

<script>
  import wepy from 'wepy'
  export default class Test extends wepy.page {
    data = {
      obj: {
        list: []
      },
      listObj: [{
        list: []
      }],
      pureList: []
    }
    computed = {
      objListLength () {
        return this.obj.list.length
      },
      objList () {
        return this.obj.list
      },
      pureListLength () {
        return this.pureList.length
      },
      listObjList () {
        return this.listObj[0].list
      }
    }
    methods = {
      test () {
        this.obj.list.push(1)
        this.pureList.push(1)
        this.listObj[0].list.push(1)
      }
    }
  }
</script>