async

• 父元件使用 :syncVal.sync="val"

  <template>
      <section class="parent">
          <son :syncVal.sync="val"></son>
      </section>
  </template>
  <script>
  import Son from "@/components/test/Son";
  export default {
    data() {
      return {
        val: 1
      };
    },
    components: {
      Son
    }
  };
  </script>
   
  

• 子元件使用 this.$emit("update:syncVal", this.$attrs.syncVal + 1);

  <template>
      <section class="son">
          <span>{{$attrs.syncVal}}</span>
          <button @click="clickFn">點選</button>
      </section>
  </template>
  <script>
  export default {
    methods: {
      clickFn() {
        this.$emit("update:syncVal", this.$attrs.syncVal + 1);
      }
    }
  };
  </script>
   
  

model

• 父元件使用 v-model

  <template>
      <section class="parent">
          <son v-model="val"></son>
      </section>
  </template>
  <script>
  import Son from "@/components/test/Son";
  export default {
    data() {
      return {
        val: 10
      };
    },
    components: {
      Son
    }
  };
  </script>
   
  

• 子元件使用 this.$emit("changParent", this.val1 + 1);

  <template>
      <section class="son">
          <span>{{val}}</span>
          <button @click="clickFn">點選</button>
      </section>
  </template>
  <script>
  export default {
    // 子元件自定義 prop 和 event
    model: {
      prop: "val",
      event: "changParent"
    },
    props: ["val1"],
    created() {
      console.dir(this);
    },
    methods: {
      clickFn() {
        this.$emit("changParent", this.val1 + 1);
      }
    }
  };
  </script>

• 子元件使用的另外一種方法，value 是必須的，this.$emit("input", this.value + 1);

  <template>
      <section class="son">
          <span>{{value}}</span>
          <button @click="clickFn">點選</button>
      </section>
  </template>
  <script>
  export default {
    props: {
      value: {
        default: ""
      }
    },
    created() {
      console.dir(this);
    },
    methods: {
      clickFn() {
        this.$emit("input", this.value + 1);
      }
    }
  };
  </script>

連結

• https://www.cnblogs.com/gsgs/p/7294160.html