FizzBuzz Benchmarks

fizzbuzz.js

var FizzBuzz = {

  'switch': function(N) {
    var result = [];
    for (var i = 1; i <= N; i++) {
      switch (i % 15) {
        case 0:
          result.push('FizzBuzz');
          break;
        case 3:
        case 6:
        case 9:
        case 12:
          result.push('Fizz');
          break;
        case 5:
        case 10:
          result.push('Buzz');
          break;
        default:
          result.push(i);
      }
    }
    return result;
  },

  'concat': function(N) {
    var result = [];
    for (var i = 1; i <= N; i++) {
      var entry = '';
      if (i % 3 === 0) {
        entry += 'Fizz';
      }
      if (i % 5 === 0) {
        entry += 'Buzz';
      }
      result.push(entry || i);
    }
    return result;
  },

  'mod': function(N) {
    var result = [];
    for (var i = 1; i <= N; i++) {
      if (i % 15 === 0) {
        result.push('FizzBuzz');
      } else if (i % 3 === 0) {
        result.push('Fizz');
      } else if (i % 5 === 0) {
        result.push('Buzz');
      } else {
        result.push(i);
      }
    }
    return result;
  },

  'countdown': function(N) {
    var result = [];
    for (var i = 1, fizz = 2, buzz = 4; i <= N; i++, fizz--, buzz--) {
      if (fizz === 0 && buzz === 0) {
        result.push('FizzBuzz');
        fizz = 3;
        buzz = 5;
      } else if (fizz === 0) {
        result.push('Fizz');
        fizz = 3;
      } else if (buzz === 0) {
        buzz = 5;
        result.push('Buzz');
      } else {
        result.push(i);
      }
    }
    return result;
  },

  'bitwise': function(N) {
    var result = [];
    var acc = 810092048;
    var c = 0;
    for (var i = 1; i <= N; i++) {
      c = acc & 3;
      acc = acc >> 2 | c << 28;
      if (c === 0) {
        result.push(i);
      } else if (c === 1) {
        result.push('Fizz');
      } else if (c === 2) {
        result.push('Buzz');
      } else {
        result.push('FizzBuzz');
      }
    }
    return result;
  }

};

var runTests = function(N) {
  var padding = new Array(Math.max.apply(null, Object.keys(FizzBuzz).map(function(item) {
    return item.length;
  }))).join(' ');
  for (var method in FizzBuzz) {
    var startTime = new Date().getTime();
    FizzBuzz[method](N);
    console.log('%s: %s%sms', method, padding.slice(method.length - 1), new Date().getTime() - startTime);
  }
};

runTests(+process.argv[2] || 10000000);