vue3 provide与inject的使用小技巧分享

<template>
  <div class="text">盒子 {{state.name}}</div>
  <div class="box">
   <Child/>
  </div>
</template>

<script lang="ts">
import { defineComponent, ref, reactive, provide } from 'vue'
import Child from './components/child.vue'
export default defineComponent({
  components:{
    Child
  },
  setup() {
    const state: any = reactive({
      name: 'zlz',
      age: 24
    })
    const update = (key: string, val: any): void => {
      state[key] = val
    }
    provide('ref2', {
      val: state,  // val需要传递的值
      update // 更新传递的值的方法
    })
    return {
      state
    }
  }
})
</script>

const state: any = reactive({
  name: 'zlz',
  age: 24,
  update // 更新state的方法
})
provide('ref2', state)

<template>
  <div class="box">
    <div class="box">child组件</div>
    <Son/>
  </div>
</template>

<script>
import { defineComponent, reactive, toRaw } from 'vue'
import Son from './son.vue'
export default defineComponent({
  components:{
    Son
  },
  setup() {
  }
})
</script>

<template>
  <div class="box">
    son组件 {{ref2.val.age}}
  </div>
  <button @click="handleClick">
    子组件点击
  </button>
</template>

<script>
import { inject } from 'vue'
export default {
  setup() {
    const ref2 = inject('ref2')
    const handleClick = () => {
      const key = 'age'
      ref2.update(key, 111) // 调用传递下来的方法去更新父组件的值
    }
    return {
      ref2,
      handleClick
    }
  }
}
</script>

<ul>
  <li v-for="user in users" v-if="user.active">
    {{ user.name }}
  </li>
</ul>

<ul v-if="active">
  <li v-for="user in users">
    {{ user.name }}
  </li>
</ul>

// js
let usersActive = computed(()=>users.filter(user => user.active))
// template
<ul>
    <li v-for="user in usersActive">
      {{ user.name }}
    </li>
</ul>