Feature proposal: Array#indexOf(iterator, i, context)

[Rafael Raposo]

Hello,

Don't know if this is going to be of any use for someone or to enter the core, but I needed to write a new indexOf that uses an iterator to get the index from an Array. Array#find finds the value, but I need the index so here is the code if you want to take a look. I know that maybe Array#indexOf will be deprecated for native code use, but I find this version  with iterator quite useful.

(function(){

    Array.prototype._indexOf = Array.prototype.indexOf;

    function indexOf(itemIt, i, context){

        //not an iterator, uses regular indexOf

        if(!Object.isFunction(itemIt)) {

            return this._indexOf(itemIt, i);

        }

        //item as a function is an iterator

        //NaN 'i' is the context, nullifies 'i' to initialize it correctly after

        if(!Object.isNumber(i)) {

            context = i;

            i = null;

        }

        i || (i = 0);

        var length = this.length;

        if (i < 0) i = length + i;

        for (; i < length; i++)

            if (itemIt.call(context, this[i], i)) {

                return i;

            }

        return -1;

    }

    //redefines indexOf

    Array.prototype.indexOf = indexOf;

})();

I kept the old indexOf for no-iteretor equality cases.

I know that this won't work on a function array if you want the index of a function inside it. Maybe there should/could be an specific indexOfIt() method instead of overriding the regular Array#indexOf method. What do you think?

Cheers,

Rafael