202 Happy Number.js

/**
 * @param {number} n
 * @return {boolean}
 */
var isHappy = function(n) {
  if (n === null) {
    return false;
  }

  var val = n;
  var hash = {};

  while (!hash[val]) {
    if (val === 1) {
      return true;
    }

    hash[val] = true;

    var sn = val + "";
    var sarr = sn.split("");
    var total = 0;

    for (var i = 0; i < sarr.length; i++) {
      si = parseInt(sarr[i]);
      total += Math.pow(si, 2);
    }

    val = total;
  }

  return false;
};