Annotated.js

function Product (options) {

  //I like to have all my instance variables in one accessible place
  this.priceChangeListeners = new Array();
  this.name = null;
  this.price = 0.0;
  this.upc = null;
  this.image_path = null;
  // Was: if (options.name == undefined)
  // In javascript, many values evaluate to false, including undefined
  // These are known as falsy values, and it can be helpful to check them all at once
  if (options.name) {
    this.name = "TBD";
  } else {
    this.name = options.name;
  }
  // Was: if (options.price > 0)
  // Always try to use decimals for any values that may become decimals
  // Also, check for the existence of the property before doing any comparisons
  if (options.price && options.price > 0.0) {
    //Math.round(options); <- options is just a javascript object, which can't be rounded i.e. {price: 10.34, name: "Test"}
    this.price = options.price;
  }
  if (typeof options.upc == 'string') {
    this.upc = new UPC(options.upc);
  } else if (typeof options.upc == 'object') {
    this.upc = options.upc;
  // Was: else if (options.upc == null)
  // The property you are trying to access will return undefined if it isn't there, not null  
  } else if (typeof options.upc == 'undefined') {
    this.upc = new UPC();
  }
  if (options.image_path[0] == '/'){
    var j = options.image_path.search(".jpg");
    var p = options.image_path.search(".png");
    var g = options.image_path.search(".gif");
    var jp= options.image_path.search(".jpeg");
  }
  if (j > -1 || p > -1 || g > -1 || jp > -1)
    this.image_path = options.image_path;
  }
}

Product.prototype.addPriceChangeListener = function(listener) {
  this.priceChangeListeners.push(listener);
  //Return the index of the listener, so we can have a reference to remove it with
  return this.priceChangeListeners.length-1;
};

Product.prototype.removePriceChangeListener = function(listenerIndex){
  //Set the listener in array to undefined
  //Because of this, we also need to add a check in setPrice to make sure the function is defined before trying to call it
  delete this.priceChangeListeners[listenerIndex];
};

Product.prototype.setPrice = function(newPrice) {
  if (newPrice > 0.0) {
    this.price = newPrice;
    for (var i = 0; i < this.priceChangeListeners.length; i++){
      if (this.priceChangeListeners[i]) {
        this.priceChangeListeners[i](newPrice, this);
      }
    }
  }
};

Product.prototype.getPrice = function() {
  return this.price;
}''

clean.js

function Product (options) {

  this.priceChangeListeners = new Array();
  this.name = null;
  this.price = 0.0;
  this.upc = null;
  this.image_path = null;

  if (options.name) {
    this.name = "TBD";
  } else {
    this.name = options.name;
  }

  if (options.price && options.price > 0.0) {
    this.price = options.price;
  }

  if (typeof options.upc == 'string') {
    this.upc = new UPC(options.upc);
  } else if (typeof options.upc == 'object') {
    this.upc = options.upc;
  } else if (typeof options.upc == 'undefined') {
    this.upc = new UPC();
  }

  if (options.image_path[0] == '/'){
    var j = options.image_path.search(".jpg");
    var p = options.image_path.search(".png");
    var g = options.image_path.search(".gif");
    var jp= options.image_path.search(".jpeg");
  }

  if (j > -1 || p > -1 || g > -1 || jp > -1)
    this.image_path = options.image_path;
  }
}

Product.prototype.addPriceChangeListener = function(listener) {
  this.priceChangeListeners.push(listener);
  return this.priceChangeListeners.length-1;
};

Product.prototype.removePriceChangeListener = function(listenerIndex){
  delete this.priceChangeListeners[listenerIndex];
};

Product.prototype.setPrice = function(newPrice) {
  if (newPrice > 0.0) {
    this.price = newPrice;
    for (var i = 0; i < this.priceChangeListeners.length; i++){
      if (this.priceChangeListeners[i]) {
        this.priceChangeListeners[i](newPrice, this);
      }
    }
  }
};

Product.prototype.getPrice = function() {
  return this.price;
};