Question

func parent(children){
    for(var i =0;i<children.length;i++){
       this.children[i] = new Child(fname, lname);
    }
 this.printNames = function(){
          for(var i =0;i<this.children.length;i++){
      console.log(this.children[i].fname);
    }
  }
}
func child(fname,lname){
 this.fname = fname;
 this.lname = lname;
 this.changefname = function(_fname){
 this.fname = _fname;
 this.emit('NameChanged');
 }
}

我该如何做，

parentObj.children.on("NameChanged", parentObj.printNames);

我想听一听子集合中子Obj发出的事件，并调用父Object中的函数。

Answer 1

这不是太复杂，当你想要一个对象发出一个事件时，你需要给对象赋值events.EventEmitter，当你这样做时，它不能保存字符串或数字而是一个事件。

使用对象时的示例代码

var events = require('events');

var example_emitter = new events.EventEmitter;

var myObj = {};

//Basic index of an object

myObj['someevent'] = new events.EventEmitter;

myObj['someevent'].on("somemessage", function(message){
  console.log(message);
})

myObj['someevent'].emit("somemessage", "this is some message");

//Getting to more low level

myObj['element'] = {};
myObj['element']['secondevent'] = new events.EventEmitter;

myObj['element']['secondevent'].on("anotherMessage", function(message){
  console.log('the length of the message is ' + message.length + ' the message is ' + message);
})

myObj['element']['secondevent'].emit("anotherMessage", 'hello there');

以下是使用数组的示例代码。为了详细说明我上面所说的内容，我将someArray，1和2设置为3，当我将这三个索引设置为for循环中的事件对象，它们的值被覆盖，因此它们成为事件对象，当您记录它们时，它们将不会打印1，2，3但{{1 }}，eventObj，eventObj。

eventObj

因此，为了使元素像事件监听器一样，您需要首先通过创建//Working with arrays var someArray[1, 2, 3]; for(var i = 0; i < someArray.length; i++){ someArray[i] = new events.EventEmitter; //changing the values someArray[i].on('printTheIndex', function(){ console.log(someArray[i]); }); someArray[i].emit('printTheIndex'); // the indexes are now event objects, they will not log 1,2,3 but objects of events }

将其值转换为事件对象

如何监听子类对象中发出的事件

1 个答案: