Brace is an extension to Backbone that adds mixins and self-documenting attributes & events.
Brace allows:
- "namedEvents" on Models, Collections, Views and Routers, which is a collection of exposed events
- "namedAttributes" on Models, which is a collection of exposed attributes - ie a model schema
Both namedEvents and namedAttributes are arrays of strings. namedAttributes can also be an object.
:::javascript
var Person = Brace.Model.extend({
namedAttributes: ["name"],
namedEvents: ["sleep"]
});
For each attribute in namedAttributes, get[Attribute] and set[Attribute] methods are generated:
:::javascript
var person = new Person();
person.setName("Tim");
person.getName() // Returns "Tim"
Backbone models' get() and set() validate attributes:
:::javascript
person.get("name"); // ok
person.set("name", "Timmy"); // ok
person.set({
name: "Timothy"
}); // ok
person.get("lost"); // throws exception
person.set("lost", "frequently"); // throws exception
person.set({
lost: "frequently"
}); // throws exception
The types of your namedAttributes are validated and coerced when namedAttributes is an object:
:::javascript
var People = Brace.Collection.extend();
var Person = Brace.Model.extend({
namedAttributes: {
name : "string", // validate primitives with typeof
otherNames : [ "string" ], // validate typed array-likes
birthDate : Date, // validate arbitrary constructors with instanceof,
// calls `new constructor(rawValue)` if necessary
children : People, // validate Backbone.Collections,
// coerces arrays and contained models if necessary
attributes : Array, // validate untyped array-likes
metadata : null || undefined || false // skip validation completely
}
});
People.model = Person;
var person = new Person({ name : 'Enigma' }); // ok
person.set('name', null); // ok
person.set('name', 'Nazim'); // ok
person.set('name', 4); // throws exception
person.set('otherNames', [ 'Ahmed' ]); // ok
person.set('otherNames', [ 1, 4 ]); // throws exception
person.set('attributes', [ 'one', 2, {} ]); // ok
person.set('attributes', 'The Dude'); // throws exception
person.set('birthDate', 'Mar 12 1960'); // ok
person.get('birthDate').toString(); // "Sat Mar 12 1960 00:00:00 GMT+1100 (AUS Eastern Daylight Time)"
person.set('children', [ { name : 'Adam' }, { name : 'Mariam' }, { name : 'Sarah' } ]); // ok
person.get('children'); // returns People instance containing three Person models.
For each event in namedEvents, on[Event] and trigger[Event] methods are generated:
:::javascript
person.onSleep(function(dream) { console.log("Dreaming about " + dream); } );
person.triggerSleep("Unicorns");
Brace allows a "mixins" property on models, views, collections and routers:
:::javascript
var Loggable = {
log: function(msg) {
console.log(msg);
}
};
var PersonView = Brace.View.extend({
mixins: [Loggable],
initialize: function() {
this.log("Initialized");
}
});
namedAttributes and namedEvents in mixins are respected:
:::javascript
var Selectable = {
namedAttributes: ["selected"],
namedEvents: ["select"],
initialize: function() {
this.on("change:selected", _.bind(function(model, selected) {
if (selected) {
this.triggerSelect();
}
}, this));
}
};
var Person = Brace.Model.extend({
mixins: [Selectable]
});
var person = new Person();
person.onSelect(function() { console.log("Person was selected"); });
person.setSelected(true);
person.getSelected();
person.triggerSelect();
Additionally, Brace composes
- initialize() on all objects, and
- defaults and validate() on models
All other name clashes between mixins fail violently and forcefully at class declaration time (not at instance construction time).
:::javascript
var Runnable = {
run: function() {}
};
var RunModel = Brace.Model.extend({
mixins: [Runnable],
run: function() {}
}); // throws "Mixin error: class already has property 'run' defined"