happyNumberFinder.js

/* JS Happy Number Finder
Run from command line with node happyNumberFinder.js [number]
*/

var _ = require('underscore');

var HappyNumberFinder = (function(_){

  "use strict";

  /* Private */
  var results_array = [];
  
  function splitNumberIntoPieces(number) {
    var numberStringArray = number.toString().split('');
    return _.map(numberStringArray, function(n) { return parseInt(n); });
  }

  function squareArrayAndSum(number_array) {
    var squaredSums = _.chain(number_array)
      .map(function(n) { return n * n; })
      .inject(function(total_sum, eachNum) {
        return total_sum += eachNum;
      }, 0)
      .value();

    return squaredSums;
  }

  function checkIfNumberIsHappy(input) {
    var numInPieces = splitNumberIntoPieces(input);
    var squaredNumResult = squareArrayAndSum(numInPieces);

    if (squaredNumResult == 1) {
      console.log("-->  This number is happy");
      results_array = []; /* clear for repeated use of function */
    } else {
      returnOrContinue(squaredNumResult);
    }
  }

  function returnOrContinue(number) {
    console.log(number);

    if (results_array.indexOf(number) != -1) {
      console.log("This number is not happy");
      return;
    } else {
      results_array.push(number);
      checkIfNumberIsHappy(number);
    }
  }

  /* Public */
  function checkForNumber(input) {
    checkIfNumberIsHappy(input)
  }

  return {
    check: checkForNumber
  }

}(_));

HappyNumberFinder.check(process.argv[2]);