text: function broadcast (componentName, eventName, params = '') {
    this.$children.forEach(child => {
      const name = child.$options.name
      if (name === componentName) {
        child.$emit.apply(child, [eventName].concat(params))
      } else {
        broadcast.apply(child, [componentName, eventName].concat([params]))
      }
    })
  }
  
  export default {
    methods: {
      // 向上派发
      dispatch (componentName, eventName, params = '') {
        console.log('触发 dispatch')
        let parent = this.$parent || this.$root
        let name = parent.$options.name
        while (parent && (!name || name !== componentName)) {
          parent = parent.$parent
          if (parent) {
            name = parent.$options.name
          }
        }
        if (parent) {
          parent.$emit.apply(parent, [eventName].concat(params))
        }
      },
      // 向下广播
      broadcast (componentName, eventName, params) {
        console.log('触发 broadcast')
        broadcast.call(this, componentName, eventName, params)
      }
    }
  }