A plugin to make Backbone.js keep track of nested attributes. Download minified version.
Suppose you have a Backbone Model with nested attributes, perhaps to remain consistent with your document-oriented database. Updating the nested attribute won't cause the model's "change" event to fire, which is confusing.
var user = new Backbone.Model({
name: {
first: 'Aidan',
last: 'Feldman'
}
});
user.bind('change', function(){
// this is never reached!
});
user.get('name').first = 'Bob';
user.save();Wouldn't it be awesome if you could do this?
user.bind('change:name.first', function(){ ... });-
Download the latest version here, and add
backbone-nested.jsto your HTML<head>, afterbackbone.jsis included (tested against jQuery v1.7.1, Underscore v1.3.1 and Backbone v0.5.3).<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script> <script type="text/javascript" src="underscore.js"></script> <script type="text/javascript" src="backbone.js"></script> <script type="text/javascript" src="backbone-nested.js"></script>
-
Change your models to extend from
Backbone.NestedModel, e.g.var Person = Backbone.Model.extend({ ... }); // becomes var Person = Backbone.NestedModel.extend({ ... });
-
Change your getters and setters to not access nested attributes directly, e.g.
user.get('name').first = 'Bob'; // becomes user.set({'name.first': 'Bob'});
Best of all, Backbone.NestedModel is designed to be a backwards-compatible, drop-in replacement of Backbone.Model, so the switch can be made painlessly.
get() and set() will work as before, but nested attributes should be accessed using the Backbone-Nested string syntax:
// dot syntax
user.set({
'name.first': 'Bob',
'name.middle.initial': 'H'
});
user.get('name.first') // returns 'Bob'
user.get('name.middle.initial') // returns 'H'
// object syntax
user.set({
'name': {
first: 'Barack',
last: 'Obama'
}
});// object syntax
user.set({
'addresses': [
{city: 'Brooklyn', state: 'NY'},
{city: 'Oak Park', state: 'IL'}
]
});
user.get('addresses[0].state') // returns 'NY'
// square bracket syntax
user.set({
'addresses[1].state': 'MI'
});"change" events can be bound to nested attributes in the same way, and changing nested attributes will fire up the chain:
// all of these will fire when 'name.middle.initial' is set or changed
user.bind('change', function(model, newVal){ ... });
user.bind('change:name', function(model, newName){ ... });
user.bind('change:name.middle', function(model, newMiddleName){ ... });
user.bind('change:name.middle.initial', function(model, newInitial){ ... });
// all of these will fire when the first address is added or changed
user.bind('change', function(model, newVal){ ... });
user.bind('change:addresses', function(model, addrs){ ... });
user.bind('change:addresses[0]', function(model, newAddr){ ... });
user.bind('change:addresses[0].city', function(model, newCity){ ... });Additionally, nested arrays fire "add" and "remove" events:
user.bind('add:addresses', function(model, newAddr){ ... });
user.bind('remove:addresses', function(model, oldAddr){ ... });Acts like unset(), but if the unset item is an element in a nested array, the array will be compacted. For example:
user.get('addresses').length; //=> 2
user.remove('addresses[0]');
user.get('addresses').length; //=> 1Accessing a nested attribute will throw a warning in your console, because it's safer to use the getter syntax above. To silence these warnings, add an argument of {silent: true} to get():
user.get('addresses[0]'); // gives a warning in your console
user.get('addresses[0]', {silent:true}); // (silent)Pull requests are more than welcome - please add tests, which can be run by opening test/index.html.