
/**
 * @param { 组件名 } componentName 
 * @param { 事件名 } eventName 
 * @param { 参数 } params 
 */
function broadcast(componentName, eventName, params) {
  this.$children.forEach(child => {
    const name = child.$options.name;

    if (name === componentName) {
      child.$emit.apply(child, [eventName, params]);
    } else {
      broadcast.apply(child, [componentName, eventName].concat(params));
    }
  });
}

export default {
  methods: {
     派发 向上查找
    dispatch(componentName, eventName, params) {
      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));
      }
    },
     广播 向下查找
    broadcast(componentName, eventName, params) {
      broadcast.call(this, componentName, eventName, params);
    }
  }
};