How can I add an object property to the global obj

Question

I have some properties in an object that I would like to add to the global namespace. In javascript on the browser I could just add it to the window object like so:

var myObject = {
  foo : function() {
    alert("hi");
  }
  // and many more properties
};

for (property in myObject) {
  window[property] = myObject[property];
}

// now I can just call foo()
foo();

But since rhino doesn't have the global window object I can't do that. Is there an equivalent object or some other way to accomplish this?

Answer 1

I found a rather brilliant solution at NCZOnline:

function getGlobal(){
  return (function(){
    return this;
    }).call(null);
}

The key to this function is that the this object always points to the global object anytime you are using call() or apply() and pass in null as the first argument. Since a null scope is not valid, the interpreter inserts the global object. The function uses an inner function to assure that the scope is always correct.

Call using:

var glob = getGlobal();

glob will then return [object global] in Rhino.

Answer 2

Here's how I've done it in the past:

// Rhino setup
Context jsContext = Context.enter();
Scriptable globalScope = jsContext.initStandardObjects();

// Define global variable
Object globalVarValue = "my value";
globalScope.put("globalVarName", globalScope, globalVarValue);

Answer 3

You could just define your own window object as a top-level variable:

var window = {};

You can then assign values to it as you please. ("window" probably isn't the best variable name in this situation, though.)

See also: Can I create a 'window' object for javascript running in the Java6 Rhino Script Engine

Answer 4

I've not used rhino but couldn't you just use var?

i.e.

var foo = myObject.foo;
foo();

Edit: Damn knew there'd be a catch! Miles' suggestion would be the go in that case.

Answer 5

You could use this, which refers to the global object if the current function is not called as a method of an object.