jsmc_homework1.js

/////// Homework 1 ///////

var logCar = function (car) {
  car = car || {};
  car.make  = car.make  || 'anonymous car';
  car.color = car.color || 'uncolored';
  var a = /^[aeiouy]/.test(this.color) ? 'an' : 'a';
  console.log('I\'m ' + a + ' ' + car.color + ' ' + car.make);
};

var BMW = { color: 'blue', make: 'BMW' };

// --------

var Car = function (make, color) {
  if (make != null) {
    this.make = make;
  }
  if (color != null) {
    this.color = color;
  }
};

Car.prototype = {
  make: 'anonymous car',
  color: 'uncolored',
  log: function () {
    var a = /^[aeiouy]/.test(this.color) ? 'an' : 'a';
    console.log('I\'m ' + a + ' ' + this.color + ' ' + this.make);
  }
};


/////// Homework 2 ///////

Function.prototype.cached = function () {
  return (function (func) {
    var cache = {};
    return function (num) {
      if (!(num in cache)) {
        cache[num] = func(num);
      }
      return cache[num];
    };
  }(this));
};

var isPrime = (function ( num ) {
  // everything but 1 can be prime
  var prime = num != 1;
  for ( var i = 2; i < num; i++ ) {
    if ( num % i == 0 ) {
      prime = false;
      break;
    }
  }
  return prime;
}).cached();