Here you go:

  Array.prototype.map = function (func) {
    if (func.length !== 3) {
        throw new Error(
            "bad! this function you've passed must take THREE arguments. Grr!"
        );
    }
    for (let i = 0; i < this.length; i++) {
        this[i] = func(this[i], i, this);
    }
    return this;
  };

;)

(making this workable and bug free is left to the reader or multi-billion dollar corporations)

There can be a non-indexed map as well.

I'm most curious as to who uses the last argument in the JS map function!