Changing JavaScript's global object?

Question

Is there a way to change the root object in JavaScript?

For example, in browsers, the root object is \"window\". So

X = 5;
console         


        

Answer 1

If you're talking about variables, JavasScript has function scope.

X = 5;  // global variable

console.log( window.X );  // 5

(function() {
   var X = 6;  // declare a local variable by using the "var" keyword

   console.log( X );  // 6
})();

console.log( window.X );  // 5

Otherwise, you can create an Object, and add properties to it.

X = 5; 

console.log( window.X );  // 5

var obj = {};

obj.X = 6;

console.log( obj.X ); // 6

console.log( window.X );  // 5

---

EDIT: Adding another possible solution that could be used.

You could invoke an anonymous function, but set the context of the function to your X object. Then this in the function will refer to X.

var X = {};
(function(){
    this.A = 5;
    this.B = 8;
    this.C = 7;
}).call(X);
for(a in X){
    console.log(a+" is "+X[a]);
}

The .call() method (as well as the .apply() method) allow you to explicitly set the thisArgof a calling context. The first argument you pass will be howthis` is defined in the context of the invocation.

Or just pass X in as an argument.

var X = {};
(function(X){
    X.A = 5;
    X.B = 8;
    X.C = 7;
})(X);
for(a in X){
    console.log(a+" is "+X[a]);
}

Though the simplest is to simply reference it (as I noted in my answer above).

var X = {};
X.A = 5;
X.B = 8;
X.C = 7;
for(a in X){
    console.log(a+" is "+X[a]);
}

---

or use a module pattern:

   /****** I'm guessing at the use of "global" here ********/
global.myNamespace = (function(global,undefined) {

    // define the object to be returned
    var X = {};

    //  define private local variables
    var a_local = 'some value';
    var another_local = 'some other value';

    // define private functions
    function myFunc() {
        // do something with local variables
    }

    // give the return object public members
    X.someProperty = 'some value';
    X.anotherProperty = 'another value';
    X.publicFunc = function() {
        //do something with the local variables
        //    or public properties
    };
    X.anotherFunc = function() {
        //do something with the local variables
        //    or public properties
    };
    // return the object
    return X;

})(global);

console.log(myNamespace);