Default options provided for when a new control is created without values set in options.

defaults provides default values for a Control's options. Options passed into the constructor function will be shallowly merged into the values from defaults in setup, and the result will be stored in this.options.

Message = Control.extend({
  defaults: {
    message: "Hello World"
  }
}, {
  init: function(){
    this.element.text( this.options.message );
  }
});

new Message( "#el1" ); //writes "Hello World"
new Message( "#el12", { message: "hi" } ); //writes hi

Shared Properties

New instances of a Control will create a shallow copy of the default options. Be aware as shallow copies keep a reference to object types, such as objects, maps and computes.

var Sample = Control.extend({
  defaults: {
    computedProp: can.compute(),
    primitiveProp: 'sample'
  }
}, {});

var a = new Sample('div');
var b = new Sample('li');

//`computedProp` will be shared across instances of the `Sample` control.
//a.options.computedProp === b.options.computedProp