Ember.js Dynamic Model Properties

Question

Ember.js (and Ember Data) allows me to specify properties of a model, such as id, label and description. But I allow my users to add their own properties to any model, which are obviously impossible for me to know about. Is there any way I can dynamically add properties to a model at runtime? (And more importantly, will Ember.js recognize changes on those properties and save them?)

Answer 1

Ember defines object properties via Ember.defineProperty. The signature is Ember.defineProperty(object, propertyName, function). For instance to define a lorem property backed by _lorem, you can use

Ember.defineProperty(this, 'lorem', 
  Ember.computed(function (key, value) {
    if (value) {
      this.set('_lorem', value);
      return value;
    } else {
      return this.get('_lorem');
    }
  }  
));

You can call this method based in a user input handler when the propertyName is dynamic. This sort of thing is best suited for extending the Meta object system. Caution is advised, especially with user input!