look and say

lookandsay.js

/**
 * look and say
 * 
 * Reference:
 * 1.https://github.com/bkarak/fuzzer-fat-fingers/blob/master/src/tasks/LookAndSay/LookAndSay.js
 * 2.https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace
 */

function lookandsay(str) {
    return str.replace(/(.)\1*/g, function(seq, p1){return seq.length.toString() + p1})
}
var num = "1";

for (var i = 10; i > 0; i--) {
    console.log(num);
    num = lookandsay(num);
}