Question

Is there any way to refer to the function object that you’re currently executing in? If it’s not a method of any object or not called with .call() or .apply(), the this pointer is likely just window, not the function object.

I often use a design pattern like this for global variables that I want scoped to a particular function as this keeps them out of the top level namespace:

function generateRandom() {
    if (!generateRandom.prevNums) {    
        generateRandom.prevNums = {};    // generateRandom.prevNums is a global variable
    }
    var random;
    do {
        random = Math.floor((Math.random() * (99999999 - 10000000 + 1)) + 10000000);
    } while (generateRandom.prevNums[random])
    generateRandom.prevNums[random] = true;
    return(random.toString());
}

But, I’d rather not have to spell out the function name every time I want to use a variable scoped to that object. If the name of the function ever changes, there are then a lot of places to change the name.

Is there any way to get the currently executing function object?

Answer 1

I don’t think there’s any way to do exactly what you ask, but you could use a closure for your function-local static variables instead.

You can easily achieve this using an IIFE:

var generateRandom = (function() {
    //any function's static variables go here
    var prevNums = {};

    return function() {
        //function code goes here
        var random;
        do {
            random = Math....
        }

        prevNums[random] = true; 

        return random.toString();
    };
})();