简单聊聊vue2.x的$attrs和$listeners

2024-04-02 19:55

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$attrs

$attrs 用于多层次组件传递参数（组件标签的attribute，class和style除外），爷爷辈组件向孙子辈组件传递参数（注：参数不能被父辈prop识别，一旦被父辈prop识别且获取，则孙子辈组件不能获取到该参数）

写法如下：（注：v-bind不能用简写 :）

<grand-son v-bind="$attrs" />

下面举个栗子：

爷爷（GrandFather）向父亲（Father）传递一个 msg1

向孙子（GrandSon）传递一个 msg2，孙子会一并接收 msg1（然而被父亲接走了，所以孙子收不到 msg1）

<!-- GrandFather.vue -->
<template>
  <div>
    GrandFather:
    <father :msg1="msg1" :msg2="msg2" />
  </div>
</template>

<script>
import Father from './Father.vue'
export default {
  components: { Father },
  data() {
    return {
      msg1: 'msg1',
      msg2: 'msg2'
    }
  }
}
</script>

<!-- Father.vue -->
<template>
  <div>
    Father: {{ msg1 }}
    <grand-son v-bind="$attrs" />
  </div>
</template>

<script>
import GrandSon from './GrandSon.vue'
export default {
  components: { GrandSon },
  props: ['msg1']
}
</script>

<!-- GrandSon.vue -->
<template>
  <div>GrandSon: {{ msg1 }}{{ msg2 }}</div>
</template>

<script>
export default {
  props: ['msg1', 'msg2']
}
</script>

界面现实结果：

GrandFather:
Father: msg1
GrandSon: msg2

$listeners

$listeners 用于多层次组件传递事件监听器，爷爷辈组件向父辈、孙子辈、曾孙子辈……组件传递事件（与 $attrs 不同，不存在半路被拦截的情况）

写法如下：（注：v-on 不能用简写 @，虽然不报错，但是也不生效）

<grand-son v-on="$listeners" />

下面继续使用爷爷-> 父亲 -> 孙子的栗子：

爷爷（GrandFather）给父亲（Father）绑定一个 click 事件

父亲通过点击 div 触发 click 事件，同时向孙子（GrandSon）传递 $listeners

<!-- GrandFather.vue -->
<template>
  <div>
    GrandFather:
    <father :msg1="msg1" :msg2="msg2" @click="handleClick" />
  </div>
</template>

<script>
import Father from './Father.vue'
export default {
  components: { Father },
  data() {
    return {
      msg1: 'msg1',
      msg2: 'msg2'
    }
  },
  methods: {
    handleClick() {
      console.log('trriger click')
    }
  }
}
</script>

<!-- Father.vue -->
<template>
  <div>
    <div @click="handleFatherClick">Father: {{ msg1 }}</div>
    <grand-son v-bind="$attrs" v-on="$listeners" />
  </div>
</template>

<script>
import GrandSon from './GrandSon.vue'
export default {
  components: { GrandSon },
  props: ['msg1'],
  methods: {
    handleFatherClick() {
      console.log('father click')
      this.$emit('click')
    }
  }
}
</script>

<!-- GrandSon.vue -->
<template>
  <div @click="handleSonClick">GrandSon: {{ msg1 }}{{ msg2 }}</div>
</template>

<script>
export default {
  props: ['msg1', 'msg2'],
  methods: {
    handleSonClick() {
      console.log('grandson click')
      this.$emit('click')
    }
  }
}
</script>

界面：