jquery - How to add multiple callbacks to a javascript method? - Stack Overflow

admin管理员组

文章数量:1278979

I have created a simple javascript class using the 'function' technique. In the class I have a websocket listener which triggers a function when a certain message is received. I could easily add an external callback to it, as follows

function MyClass() {
    self = this; // to access main object from methods

    // websocket definition

    function websocketMessageInterpreter(message){
       if(message == "Hello!")  onHelloMessageBase();
     }

    function onHelloMessageBase(param){

    // call user defined callback
    self.userDefinedCallback(param);
    }
    this.userDefinedCallback= function(param){}; //default empty callback
}

Externally I use this as

var myObject = new MyClass();
myObject.userDefinedCallback = function(){alert("Someone said hello!");};

Is there a model where I could do something like this?

myObject.userDefinedCallback += function1;
myObject.userDefinedCallback += function2;

and maybe later

myObject.userDefinedCallback -= function1;

I have created a simple javascript class using the 'function' technique. In the class I have a websocket listener which triggers a function when a certain message is received. I could easily add an external callback to it, as follows

function MyClass() {
    self = this; // to access main object from methods

    // websocket definition

    function websocketMessageInterpreter(message){
       if(message == "Hello!")  onHelloMessageBase();
     }

    function onHelloMessageBase(param){

    // call user defined callback
    self.userDefinedCallback(param);
    }
    this.userDefinedCallback= function(param){}; //default empty callback
}

Externally I use this as

var myObject = new MyClass();
myObject.userDefinedCallback = function(){alert("Someone said hello!");};

Is there a model where I could do something like this?

myObject.userDefinedCallback += function1;
myObject.userDefinedCallback += function2;

and maybe later

myObject.userDefinedCallback -= function1;

• javascript
• jquery
• callback

Share Improve this question Follow asked Jan 16, 2013 at 12:34 malbermalber 1,07344 gold badges1616 silver badges2424 bronze badges 1

• you could write nested functions into the callback – Johnny000 Commented Jan 16, 2013 at 12:39

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 11

The usual way to do this is to have an array of callbacks, and methods like addCallback(callback) and removeCallback(callback) to let users of the API add and remove callbacks.

addCallback is basically:

function addCallback(callback) {
    if (this.callbacks.indexOf(callback) < 0) {
        this.callbacks.push(callback);
    }
}

removeCallback is basically:

function removeCallback(callback) {
    var index;
    if ((index = this.callbacks.indexOf(callback)) >= 0) {
        this.callbacks.splice(index, 1);
    }
}

If you need to support really old browsers like IE6 which may not have Array#indexOf, since you're using jQuery, you can use jQuery.inArray instead.

本文标签： jqueryHow to add multiple callbacks to a javascript methodStack Overflow