记录vue认识过程中1.0到2.0不同

• v-el v-ref >> ref
  2.0中v-el和v-ref被废除，ref属性代替
  ref is used to register a reference to an element or a child component.The reference will be registered under the parent component’s $refs object. If used on a plain DOM element, the reference will be that element; if used on a child component, the reference will be component instance:

<!-- vm.$refs.p will be the DOM node -->
<p ref="p">hello</p>

<!-- vm.$refs.child will be the child comp instance -->
<child-comp ref="child"></child-comp>

this.$refs.p
this.$refs.child

• 2.0中去掉了events实例属性和$dispatch,$broadcast事件绑定
  • 1.0 组件通信方式
    子组件

    this.$dispatch('eventName', 'hello')
    

    父组件

     event:{
     'eventName':function(msg) {
         console.log(msg)
       }
     }
    

  • 2.0中可以通过一个空vue对象实现一个事件处理器
    main.vue

    new Vue({
      el: '#main',
      data () {
        return {
          eventsHub: new Vue()
         }
      },
      router: router,
      render: h => h(App)
    })
    

    子组件

    this.$root.eventsHub.$emit('eventName','hello')
    

    父组件

    created () {
      this.$root.eventsHub.$on('eventName',(msg) => {
        console.log(msg)
      })
    }
    

    https://vuejs.org/v2/guide/migration.html#dispatch-and-broadcast-replaced