Pass anonymous method belonging to object as an argument- Javascript

Question

I have an object with a method, I want to pass the method as an argument to another function. However the function must know the object associated with the method (or it can't access values assigned to the object after creation).

Is there a way to this without resorting to passing the object/method as a string?
(ex not using: window[function_name];)

function My_Object(name){
    this.name = name;
}

My_Object.prototype.My_Method = function(){
     alert(this.name);
}

//This is the function that passes the method
function Runner(){
     var NewObject = new My_Object('Andre');
     test(NewObject.My_Method);//this is where it should break
}

//This is the function that receives and calls the Object's method
function test(func){
    func();
}

it would help if you paste some code that shows us what you want to accomplish — AlexanderBrevig
– AlexanderBrevig, Commented Sep 17, 2014 at 16:57
just pass the object itself to the function, the function can then access everything it needs. Some code samples would help give more context-specific answers. — Sebastien Daniel
– Sebastien Daniel, Commented Sep 17, 2014 at 16:57
This is totally a duplicate. My Google-fu is just letting me down. — Matt
– Matt, Commented Sep 17, 2014 at 16:58

friedi · Accepted Answer · 2014-09-17 17:19:09Z

2

Use a anonymous function:

//This is the function that passes the method
function Runner(){
     var NewObject = new My_Object('Andre');
     test(function() {
         NewObject.My_Method();
     });
}

or bind your method to NewObject like this:

//This is the function that passes the method
function Runner(){
     var NewObject = new My_Object('Andre');
     test(NewObject.My_Method.bind(NewObject));
}

And if you don't change your test function in the future, you can simple call the function you want to test in the Runner function:

//This is the function that passes the method
function Runner(){
     var NewObject = new My_Object('Andre');
     NewObject.My_Method(); // directly call the function
}

edited Sep 17, 2014 at 17:19

answered Sep 17, 2014 at 17:12

friedi

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Comments

Adam Jenkins · Accepted Answer · 2014-09-17 17:08:23Z

1

The comment about execution context is important here:

//This is the function that passes the method
function Runner(){
     var NewObject = new My_Object('Andre');
     test(NewObject.My_Method,NewObject);
}

//This is the function that receives and calls the Object's method
function test(func,ctx){
    func.apply(ctx || this);
}

answered Sep 17, 2014 at 17:08

Adam Jenkins

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