組件通信常用方法

以下demo github地址： feature/communication分支

• props

<!-- Child.vue -->
  <template>
      <div>
          <p>{{msg}}</p>
      </div>
  </template>
  <script>
  export default {
     // props: ['msg'],    //基本用法
    props: {
        msg: {
              type: String,
              //required: true,  // 默認false，是否必傳  必傳自然就沒有default
              default: ""  
        }
    }
  }
  </script>

<!-- Parent.vue -->
  <template>
      <Child msg='from parent to child message'></Child>
  </template>
  <script>
  import Child from './Child.vue'
  export default {
        components: {
            Child
        }
    }
  </script>

• $emit / $on ( 發布/訂閱)

<!-- Child.vue -->
<template>
  <div>
    <p>Child1.vue</p>
    <input type="text" v-model="val" @input="handleInput">
  </div>
</template>
<script>
  export default {
    data() {
      return {
        val : ""
      }
    },
    mounted() {
      this.handleInput();
    },
    methods : {
      handleInput () {
        this.$emit('emitEvent', this.val)
      }
    }
  }
</script>

<!-- Parent.vue -->
    <template>
        <div>
            <Child @emitEvent="getFromChild"></Child>
            <p>從child訂閱的值：{{val}}</p>
        </div>
    </template>
    <script>
    import Child from './Child.vue'
    export default {
         components: {
              Child
        },
        data() {
            return {
                val : "",
            }
        },
        methods: {
              getFromChild(args){
                  this.val = args;
              }
        }
    }
   </script>

• event bus (總線 --> $emit / $on)

//main.js
Vue.prototype.$bus = new Vue();  //注冊全局的bus 

//Bus.vue
<template>
  <div>
    <Bus1></Bus1>
    <Bus2></Bus2>
  </div>
</template>
<script>
  import Bus1 from "../components/module/Bus1";
  import Bus2 from "../components/module/Bus2";
  export default {
    components: {
      Bus1,
      Bus2
    }
  };
</script>

//Bus1.vue
<template>
  <div>
    <p>Bus1</p>
    <input type="text" v-model="inputVal" />
    <button @click="handleAddBusVal">Bus1發布</button>
  </div>
</template>

<script>
  export default {
    mounted(){
      this.$nextTick(()=>{
        this.handleAddBusVal();
      })
    },
    data() {
      return {
        inputVal: 'Event Bus1 message to Bus2'
      }
    },
    methods: {
      handleAddBusVal() {
        this.$bus.$emit('addBusVal',this.inputVal);
      }
    },
  };
</script>

// Bus2.vue
<template>
  <div>
    <p>Bus2</p>
    <p>{{busVal}}</p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        busVal: '2222'
      };
    },
    mounted() {
      this.$bus.$on('addBusVal',target=>{
        this.busVal = target
      });
    }
  };
</script>

• VueX
  VueX官方文檔