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Computed fields for Backbone.Models

Downloads And Source

Grab the source from the src folder above. Grab the most recent builds from the links below.

Standard Builds

RequireJS (AMD) Builds

Basic Use

var Model = Backbone.Model.extend({

  initialize: function(){
    // initialize all of the computed fields for this model

  // define a computed field.
  // tell it what field to `set` on the model
  // tell it what fields this one depends on
  // give it a callback function to compute the value when any dependent field changes
  someField: {
    fields: ["f1", "f2"], 
    compute: function(fields){
      return fields.f1 + "-" + fields.f2


var model = new Model({
  f1: "foo",
  f2: "bar"

// get the current value
model.get("someField"); // => "foo-bar"

// re-run the computation, `set` the current value and return it
model.someField(); // => "foo-bar"

// Handle "change" events for the computed field
model.on("change:someField", function(){
  // do stuff when the computed field changes

// `set` the fields that the computed field depends on
  f1: "boo",
  f2: "far"

// get the updated value
model.get("someField"); // => "boo-far"
model.someField(); // => "boo-far"


MIT license - see