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In JavaScript, is it possible to move inner functions from one function into the global scope? I haven't yet found any straightforward way to do this.

function moveMethodsIntoGlobalScope(functionName){
    //move all of functionName's methods into the global scope
    //methodsToPutIntoGlobalScope should be used as the input for this function.
}

//I want all of the methods in this function to be moved into the global scope so that they can be called outside this function.
function methodsToPutInGlobalScope(){
    function alertSomething(){
        alert("This should be moved into the global scope, so that it can be called from outside the function that encloses it.");
    }
    function alertSomethingElse(){
        alert("This should also be moved into the global scope.");
    }
}
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2
  • This is not possible this way, you can make methodsToPutInGlobalScope an object instead of function and then you will be able to access functions inside it. Commented Apr 24, 2013 at 17:21
  • Does methodsToPutInGlobalScope only have function declarations inside it, or is there more? For example, using eval could work, but might not be what you want if there are more than function declarations inside the function. Commented Apr 24, 2013 at 17:25

3 Answers 3

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If you don't want to make changes in methodsToPutInGLobalSpace you can use the following dirty hack:

var parts = methodsToPutInGlobalScope.toString().split('\n');
eval(parts.splice(1, parts.length - 2).join(''));

As final solution we can use:

moveMethodsIntoGlobalScope(methodsToPutInGlobalScope);
alertSomething(); //why doesn't this work?

function moveMethodsIntoGlobalScope(functionName){
    var parts = functionName.toString().split('\n');
    eval.call(window, parts.splice(1, parts.length - 2).join(''));  
}

//I want all of the methods in this function to be moved into the global scope so that they can be called outside this function.
function methodsToPutInGlobalScope(){
    function alertSomething(){
        alert("This should be moved into the global scope, so that it can be called from outside the function that encloses it.");
    }
    function alertSomethingElse(){
        alert("This should also be moved into the global scope.");
    }
}

Live demo

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9 Comments

This answer still doesn't explain how to implement moveMethodsIntoGlobalScope, which is what I was trying to do in the first place.
There's no trivial way to do this. I guess you need to parse moveMethodsIntoGlobalScope (use moveMethodsIntoGlobalScope.toString() to get the string representation) and after that declare the inner functions in the global scope.
Done! You can see the changes.
Have you tested this solution yet? I couldn't get it to work: jsfiddle.net/5CC52/1 It produces this error in the console: Uncaught ReferenceError: alertSomething is not defined
I like it, but there are some Function.prototype.toString gotchas to be wary of - stackoverflow.com/a/3379880/319878.
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Not very sophisticated, but would work.

function copyInto(arr, context) {
    //move all of functionName's methods into the global scope
    //methodsToPutIntoGlobalScope should be used as the input for this function.
    for (var i = 0; i < arr.length; i += 2) {
        var exportName = arr[i];
        var value = arr[i + 1];
        eval(exportName + "=" + value.toString());
    }
}

//I want all of the methods in this function to be moved into the global scope so that they can be called outside this function.
function methodsToPutInGlobalScope() {
    function alertSomething() {
        alert("This should be moved into the global scope, so that it can be called from outside the function that encloses it.");
    }

    function alertSomethingElse() {
        alert("This should also be moved into the global scope.");
    }

    copyInto(["alertSomething", alertSomething, "alertSomethingElse", alertSomethingElse], window);
}

methodsToPutInGlobalScope();
alertSomething();
alertSomethingElse();
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3 Comments

When methodsToPutIntoGlobalScope is called, it appears that it doesn't overwrite pre-existing functions. Is there any way to work around this problem? jsfiddle.net/5CC52/9
Strange. This will work window["alertSomething"]();. Looks like the method call is bound to the original, but an indirect method call will work.
It works with eval, like the answer from @Minko Gechev - jsfiddle.net/fiddlegrimbo/5CC52/12
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Yes, this is possible. If you declare a variable using var keyword that variable becomes local only, but if you don't it becomes a global one.

function foo(){

   var test = 'test'; // <- Using var keyword
}

foo(); // <- execute the function

console.log(test); // undefined

But if we do the same thing without var keyword:

function foo(){

   test = 'test'; // <- Using var keyword
}

foo(); // <- execute the function

console.log(test); // test

In order to make your inner functions global, you'd declare anonymous functions without var keyword 

function methodsToPutInGlobalScope() {

    alertSomething = function () {
        alert("This should be moved into the global scope, so that it can be called from outside the function that encloses it.");
    }

    alertSomethingElse = function () {
        alert("This should also be moved into the global scope.");
    }

}


methodsToPutInGlobalScope(); // <- Don't forget to execute this function


alertSomething(); // Works
alertSomethingElse(); // Works as well
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