backbone-getset

Getters & setters for your Backbone models

Usage

Write getters and setters to filter the get and set methods of Backbone models. Such functions can be used for all sorts of things:

... from providing virtual attributes:

var a = new Backbone.Model({firstName: "bob", lastName: "dobbs"})
a.getters.fullName = function () { 
  return [this.get("firstName"), this.get("lastName")].join(' ')
}
a.get("fullName") //=> "bob dobbs"

... to mutating data during set:

a.setters.value = function (v) { return Math.floor(v) }
a.set("value", 12.34)
a.get("value") //=> 12 (a.attributes.value is now 12)

... to decorating data in a get:

a.getters.value = function (v) { 
  return "$" + this.attributes.value.toFixed(2)
}
a.get("value") //=> "$12.00"

The toJSON is also extended to make use of getters if given the option, so given the above a:

a.toJSON({getters: true})
// { 
//   firstName: "bob",
//   lastName: "dobbs",
//   fullName: "bob dobbs",
//   value: "$12.00" 
// }

Getters & setters are stored on the getters and setters property of the prototype. They are inherited, but merged with the parent prototype such that all child Models have their own copy. This means that they can be added directly, as above, but more commonly would be added in the model definition.

var A = Backbone.Model.extend({
  getters: {
    name: function () {
      return "A"
    },
    type: function () {
      return "thing"
    }
  }
})

var B = A.extend({
  getters: {
    name: function () {
      return "B"
    }
  }
})

var a = new A(), b = new B()
a.get("name") //=> "A"
b.get("name") //=> "B"
b.get("type") //=> "thing"

Installation and setup

bower install backbone-getset

Or

npm install backbone-getset

Then require the module in your app. AMD and CommonJS/node are supported, as is a standard script include.

Note that the module will monkeypatch and override several methods of Backbone.Model. As such, care must be taken to not break functionality of the module by subsequently overriding those methods in your own code. If, for example, you need to override get, be sure to call the prototype method as well:

MyModel.prototype.get = function (attr) {
  var retv = Backbone.Model.prototype.get.call(this, attr)

  // do stuff

  return retv
}