Solving number to words problem from http://code-warrior.herokuapp.com.

readme.md

#Transfer word to numbers

Given an integer between 0 and 999,999, print an English phrase that describes the integer (eg, "One Thousand, Two Hundred and Thirty Four;

####power by code-warrior

index.js

var singles = [
  '', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten',
  'eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen'
];
var tenth = ['', 'ten', 'twenty', 'thirty', 'fourty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety'];
var unit = ['', 'thousand', 'million', 'billion'];

module.exports = function (n) {
  var result = [];
  var len = n.toString().length;
  while (len > 0) {
    //get the , position
    var digit = Math.ceil(len / 3) - 1;
    var num = Math.floor(n / Math.pow(1000, digit));

    var hundred = Math.floor(num / 100);
    if( hundred >= 1) {
      result.push(singles[hundred]);
      result.push('hundred');
    }

    var ten = Math.floor(num % 100);
    if( ten <= 20) {
      result.push(singles[ten]);
    } else {
      var a = Math.floor(ten / 10);
      result.push(tenth[a]);

      var b = ten % 10;
      result.push(singles[b]);
    }
    n = n % Math.pow(1000, digit);
    result.push(unit[digit]);
    len = len - 3;
  }

  return result.join(' ').trim();
}

package.json

{
  "id": "8",
  "name": "number to words",
  "level": "basic",
  "author": "CareerCup"
}

test.js

var func = require("./");
var expect = require("expect.js")

describe("func", function () {
  it("can return single words of number", function() {
    expect(func(1)).to.eql("one");
    expect(func(2)).to.eql("two");
    expect(func(3)).to.eql("three");
    expect(func(4)).to.eql("four");
    expect(func(5)).to.eql("five");
    expect(func(6)).to.eql("six");
    expect(func(7)).to.eql("seven");
    expect(func(8)).to.eql("eight");
    expect(func(9)).to.eql("nine");
  });

  it("can return double digits words", function() {
    expect(func(10)).to.eql("ten");
    expect(func(21)).to.eql('twenty one');
    expect(func(12)).to.eql('twelve');
    expect(func(13)).to.eql('thirteen');
    expect(func(17)).to.eql('seventeen');
  });

  it("can return 3 digits words", function() {
    expect(func(123)).to.eql('one hundred twenty three');
    expect(func(430)).to.eql('four hundred thirty');
    expect(func(401)).to.eql('four hundred one');
  });

  it("can return 5 digits words", function() {
    expect(func(12345)).to.eql('twelve thousand three hundred fourty five');
  });

  it("can return 6 digits words", function() {
    expect(func(123456)).to
      .eql('one hundred twenty three thousand'
          + ' four hundred fifty six');
  });
});