JavaScript implementation of http://codeiq.hatenablog.com/entry/2013/08/07/162935

fizz_buzz.js

function App() {
  this.specAndMessages = [];
};

App.prototype.addSpecAndMessage = function(spec, message) {
  this.specAndMessages.push({
    spec: spec,
    message: message
  });
};

App.prototype.run = function(until) {
  for (var i = 0; i < until; i++) {
    console.log(this.checkSpecAndGetMessage(i + 1));
  }
};

App.prototype.checkSpecAndGetMessage = function(n) {
  var spec,
      message;
  for (var i = 0, len = this.specAndMessages.length; i < len; i++) {
    if (this.specAndMessages[i].spec.isSatisfiedBy(n)) {
      return this.specAndMessages[i].message;
    }
  }
  return n;
};

function Spec(divisor) {
  this.divisor = divisor;
};

Spec.prototype.isSatisfiedBy = function(n) {
  return n % this.divisor === 0;
};

module.exports = {
  App: App,
  Spec: Spec
};

fizz_buzz_runner.js

var fizzBuzz = require('./fizz_buzz'),
    app = new fizzBuzz.App();

app.addSpecAndMessage(new fizzBuzz.Spec(15), 'fizzbuzz');
app.addSpecAndMessage(new fizzBuzz.Spec(3), 'fizz');
app.addSpecAndMessage(new fizzBuzz.Spec(5), 'buzz');

app.run(30);

naive_fizz_buzz.js

function fizzBuzz(n) {
  for (var i = 1; i <= n; i++) {
    if (i % 15 === 0) {
      console.log('fizzbuzz');
    } else if (i % 3 === 0) {
      console.log('fizz');
    } else if (i % 5 === 0) {
      console.log('buzz');
    } else {
      console.log(i);
    }
  }
}

fizzBuzz(30);