Applying context of functions to javascript variable?

Question

How do I apply the context of functions to any javascript object? So I can change what "this" means in the functions.

For Example:

var foo = {
    a: function() {
           alert(this.a);
      },
    b: function() {
           this.b +=1;
           alert (this.b);
      }

var moo = new Something(); // some object 
var moo.func.foo = foo; // right now this is moo.func
// how do I apply/change the context of the foo functions to moo?
// so this should equal moo
moo.a(); // this should work

zzzzBov · Accepted Answer · 2012-09-16 01:03:24Z

2

You can just set the function on moo:

var moo = new Something();
moo.a = foo.a;
moo.a();

...but if you want it inherited by all instances of Something, you'll need to set it on Something.prototype:

var moo;
Something.prototype = foo;
moo = new Something();
moo.a();

You have some issues in your definitions of foo.a and foo.b, as they both are self-references this.b +=1 will especially cause issues, so you may want to change the functions to something like this._b += and alert(this._b), or use differently named functions.

answered Sep 16, 2012 at 1:03

zzzzBov

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1 Comment

user166390 Over a year ago

+1 I think the [[prototype]] route is desired; it looks like a jQuery-emulation approach.

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