AdventOfCode Day10 challenge

day10.js

"use strict";

String.prototype.solve = function(){
	let str = this;
	let digit = str[0];
	let count = 1;
	let res = "";

	for (var i=1; i<str.length; i++){
		if (str[i] == digit){
			count++;
		} else{
			res += count + digit;
			digit = str[i];
			count = 1;
		}
	}

	return res + count + digit;
};

const ITERS = 50;
let timeStart = Date.now();

var puzz = "1113122113";
for (let i=0; i<ITERS; i++)	puzz = puzz.solve();
	
console.log("ELLAPSED: " + (Date.now()-timeStart) + "ms");
console.log("SOLUTION: " + puzz.length);