Backbone.Compute

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

• Development: backbone.compute.js

• Production: backbone.compute.min.js

RequireJS (AMD) Builds

• Development: backbone.compute.js

• Production: backbone.compute.min.js

Basic Use

var Model = Backbone.Model.extend({

  initialize: function(){
    // initialize all of the computed fields for this model
    Backbone.Compute(this);
  },

  // 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
model.set({
  f1: "boo",
  f2: "far"
});

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

License

MIT license - see LICENSE.md