CODEWITHSUNDEEP
javascriptfunctionthisprototype-programming
kpozin
kpozin

Reputation: 26939

Accessing the two 'this' variables in Function.prototype

I'd like to extend Function.prototype with a custom method:

Function.prototype.myMethod = function() {
     var fn = this;
     var owner = ???;
     /** ... */
};

this in that scope refers to the original function. But how do I access the this that refers to the object that "owns" the function (or whatever the outer this is at the time that fn is called)?

Upvotes: 1

Views: 156

Answers (2)

jishi
jishi

Reputation: 24614

SpiderMonkey and JScript implements a non-standard "caller" property on Function-objects. I don't know the extent of the support in other browsers.

I belive it should be accessible like this:

Function.prototype.myMethod = function() {
   var fn = this;
   var owner = this.caller;
   /** ... */
};

but haven't tested it. As I said, it's not part of ECMA standard.

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/Caller

Upvotes: 0

Ben Roux
Ben Roux

Reputation: 7426

You would need to pass it in as a parameter to the function call... not sure if this is possible in your specific usage.

myMethod(this);

function myMethod( parent ) {
    // ...

Upvotes: 1

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