Question

Consider the following code:

(function() {
    var a = 5;
    var someFunc = function() { ... };
    function anotherFunc() {
        ...
    };
})();

window.myGlobalObj = {
    init: function() {
        // and somehow here I want to  access to the IIFE context
    }
};

I want to have the execution context of IIFE in my global object. I do have access to function expression and object itself so I can pass or modify something to make it work (and no, I can’t rewrite everything inside the object or function).

Is it even possible?

Answer 1

The only way I see how that’s poosible is by using eval to simulate dynamic scopes. Do this (note that the IIFE must be placed after the global object):

window.myGlobalObj = {
    init: function() {
        // and somehow here I want to  access to the IIFE context
    }
};

(function() {
    var a = 5;
    var someFunc = function() { ... };
    function anotherFunc() {
        ...
    };

    eval("(" + String(window.myGlobalObj.init) + ")").call(window.myGlobalObj);
})();

Here’s a reference as on how to use dynamic scopes: Is it possible to achieve dynamic scoping in JavaScript without resorting to eval?

Edit: I’ve included an example to demonstrate the power of using dynamic scopes in JavaScript. You can play with the fiddle too.

var o = {
    init: function () {
        alert(a + b === this.x); // alerts true
    },
    x: 5
};

(function () {
    var a = 2;
    var b = 3;

    eval("(" + String(o.init) + ")").call(o);
}());