Question

Is there any way to introduce the local variable “iWantThisHere” here, so i can call obj.n()

var obj = { 
    test: "sure", 
    n : function(){ console.log(iWantThisHere); }
};

i tried with:

function fake(methods){
    var F =  new Function('methods', "var iWantThisHere = 'u have it', obj = {}; for( var meth in methods){ obj[meth] = methods[meth] } return obj;");

    return F(methods); }

console.log(fake(obj), fake(obj).n());

i dont want to use globals here. Imagine a modul system where each modul uses for example a util class, which is defined for example in a App object. So i always have to type for eg App.utils.map or something like that. It would be nice to have a shortcut to this util function which is a local variable in the modul context itself.

EDIT
— theres no way to do that —-

Answer 1

Introduce a closure:

var obj = (function(){
    var R = {};

    R.iWantThisHere = 5;

    R.log = function() {
        console.log(R.iWantThisHere);
    }

    return R;
})();

Demo:

> obj.log()
5
> obj.iWantThisHere = 6
> obj.log()
6

This is the most common (dare I say recommended) way to do javascript programming, by creating functions to restrict variables to a scope. It is necessary because javascript does not have block-level scoping.