Vue3中删除了过滤器filter功能-如何使用computed和methods实现filter功能

使用computed和methods实现filter功能

基础代码

`<template>
  <div id="app">
    <ul v-for="(item, index) in arr" :key="index">
      <li>快递公司:{{ item.deliverCompany }}</li>
      <li>运输状态:{{ item.expressState }}</li>
    </ul>
  </div>
</template>
<script> export default {
  data() {
    return {
      arr: [
        {
          deliverCompany: "快递1",
          expressState: "1",
        },
        {
          deliverCompany: "快递2",
          expressState: "2",
        },
        {
          deliverCompany: "快递3",
          expressState: "3",
        },
        {
          deliverCompany: "快递4",
          expressState: "4",
        },
        {
          deliverCompany: "快递5",
          expressState: "5",
        },
        {
          deliverCompany: "快递6",
          expressState: null,
        },
      ],
    };
  },
}; </script>`

`<template>
  <div id="app">
    <ul v-for="(item, index) in arr" :key="index">
      <li>快递公司:{{ item.deliverCompany }}</li>

      <li>运输状态:{{ item.expressState | showState }}</li>
    </ul>
  </div>
</template>
<script> export default {
  data() {
    return {
      ......
    };
  },

  filters: {
    showState(state) {
      switch (state) {
        case "1":
          return "待发货";
          break;
        case "2":
          return "已发货";
          break;
        case "3":
          return "运输中";
          break;
        case "4":
          return "派件中";
          break;
        case "5":
          return "已收货";
          break;
        default:
          return "快递信息丢失";
          break;
      }
    },
  },
}; </script>`

`<template>
  <div id="app">
    <ul v-for="(item, index) in arr" :key="index">
      <li>快递公司:{{ item.deliverCompany }}</li>

      <li>运输状态:{{ computedText(item.expressState) }}</li>
    </ul>
  </div>
</template>
<script> export default {
  data() {
    return {
      ......
    };
  },
  computed: {
    computedText() {

      return (state)=>{
        switch (state) {
          case "1":
            return "待发货";
            break;
          case "2":
            return "已发货";
            break;
          case "3":
            return "运输中";
            break;
          case "4":
            return "派件中";
            break;
          case "5":
            return "已收货";
            break;
          default:
            return "快递信息丢失";
            break;
        }
      };
    },
  },
}; </script>`

`<template>
  <div id="app">
    <ul v-for="(item, index) in arr" :key="index">
      <li>快递公司:{{ item.deliverCompany }}</li>

      <li>运输状态:{{ methodsText(item.expressState) }}</li>
    </ul>
  </div>
</template>
<script> export default {
  data() {
    return {
      ......
    };
  },
  methods: {
    methodsText(state) {
      switch (state) {
        case "1":
          return "待发货";
          break;
        case "2":
          return "已发货";
          break;
        case "3":
          return "运输中";
          break;
        case "4":
          return "派件中";
          break;
        case "5":
          return "已收货";
          break;
        default:
          return "快递信息丢失";
          break;
      }
    },
  },
}; </script>`

Vue3删去了重复的功能，使用computed和methods也可以实现filter功能