model.js

// The primary function of a **Model** is to manipulate and query data. For example filtering
// an array-type object should happen in a subclass of Model. Another great candidate
// for a **Model** is any object that requires an external resource such as an ajax call.
//
// Basically, any long running or long blocking operation should happen in a model.
//
// **Models** are bindable as well, so you can subscribe to notifications by calling
// `bind` with a callback and an event to subscribe to recieve events from another object.
//
// **Models** are usually encapsulated in **Views** and rarely, if ever, stand alone. 

//
propublica.Model = Base.extend({
  // The **init** method copies the passed in attributes to the instance's built in
  // **_attrs** object.
  
  MODEL_CHANGED : "changed",
  
  init : function(attrs){
    this._attrs = this._attrs || {};
    _.extend(this._attrs, attrs);
    if('id' in this._attrs) this.id = attrs.id;
    this.cid = _.uniqueId(this.name || this.id || "");
  },
  
  // Access an attribute by key.
  read : function(key){
    return this._attrs[key];
  },
  
  // Set an attribute by key. Pass in an object for key to assign multiple values.
  write : function(key, attr){
    attrs = {};
    !_.isUndefined(attr) ? attrs[key] = attr : attrs = _.extend(attrs, key);
    for(var k in attrs){
      var value = attrs[k]; 
      var old   = this._attrs[k];
      if('id' in attrs) this.id = attrs.id;
      if (!_.isEqual(old, value)) {
        this._attrs[k] = value;
        this._onchange(k, old, value);
      }
    }
    return this;
  },
  
  // delete an attribute by key.
  remove : function(key){
    var oldAttr = this._attrs[key];
    delete this._attrs[key];
    this._onchange(key, oldAttr, undefined);
    return oldAttr;
  },
    
  _onchange : function(key, old, value){
    this.fire(this.MODEL_CHANGED, this, key, old, value);
    this.fire(this.keyPath(key), this, key, old, value);
  },
  
  keyPath : function(key){
    return [key, this.MODEL_CHANGED].join("_");
  },
  
  bind : function(e, cb){
    var callbacks = (this._callbacks = this._callbacks || {});
    var list = (callbacks[e] = callbacks[e] || []);
    list.push(cb);
  },
  
  unbind : function(e, cb){
    if(!(this._callbacks && this._callbacks[e])) return;
    var list = this._callbacks[e];
    for(var i = 0; i < list.length; i++){
      if(list[i] === cb) { 
        list.splice(i, 1);
        break;
      }
    }
  },
  
  unbindAll : function(){
    delete this._callbacks;
  },
  
  fire : function(e){
    if(!this._callbacks) return;
    var list = this._callbacks[e];
    if(!list) return;
    for(var i = 0; i < list.length; i++) list[i].apply(this, arguments);
  }
  
});