Uniapp WeChat applet: Solution to key failure

<template>
  <view>
    <image v-for="(item, i) in fileList" :key="item[urlKey]" :src="item[urlKey]"></image>
  </view>
</template>

<script>
  export default {
    props: {
      urlKey: {default: 'url'},
      fileList: Array
    }
  }
</script>

<view>
  <block wx:for="{{fileList}}" wx:for-item="item" wx:for-index="i" wx:key="urlKey">
    <image src="{{item[urlKey]}}"></image>
  </block>
</view>

<template>
  <view>
    <image v-for="(item, i) in fileList" :key="key(item)" :src="item[urlKey]"></image>
  </view>
</template>

<script>
  export default {
    props: {
      urlKey: {default: 'url'},
      fileList: Array
    },
    computed: {
      key() {
        return e => e[this.urlKey]
      }
    }
  }
</script>