Javascript Array first() method

"use strict";/*from   w  ww.  ja  va2 s . c  o m*/

//zad3
Array.prototype.first = function  () {
  if (this.length === 0) {
    throw "Empty string doesn't have first element";
  }
  return this[0];
};

console.log(["a", "b", 3].first());
//console.log([].first());