Awesome model binding for Backbone.js
Inspired by Brad Phelan, Knockout.js' data-binding capabilities, and Brandon Satrom's desire to keep UJS alive.
It's easy to get up and running. You only need to have Backbone (including underscore.js - a requirement for Backbone) and jQuery in your page before including the backbone.modelbining plugin.
- Backbone.js v0.5.1 or higher
- jQuery v1.6.2 or higher
This is a plugin for Backbone.js and is built and tested against Backbone v0.5.1. It also uses jQuery to perform most of the bindng and manipulations, and is built and tested against v1.6.1. However, I am currently using this plugin in a production application with Backbone v0.3.3 and jQuery v1.5.1.
At this point, I make no guarantees of it working with any version of Backbone or jQuery, other than what it has been built and tested against. It works for me, so it may work for you with versions other than what is stated
Download the backbone.modelbinding.js file from this github repository and copy it into
your javascripts folder. Add the needed <script> tag to bring the plugin into any page
that wishes to use it. Be sure to include the modelbinding file after the backbone.js file.
Your Backbone view must have an el defined and the render method of your view needs to
execute the bindings that you define
SomeView = Backbone.View.extend({
el: "#someElement",
render: function(){
// ... render your form here
// execute the defined bindings
Backbone.ModelBindings.call(this);
}
});
Automatic bi-directional binding between your form input and your model.
The convention based binding requires no additional configuration or code in your
view, other than calling the Backbone.Modelbindings.call(this); as noted above.
With the conventions binding, your <input> fields will be bound to the views model
by the id of the input.
For example:
// something.html
<input id='name'>
// something.js
SomeModel = Backbone.Model.extend();
SomeView = Backbone.View.extend({
render: function(){
// ... render your form here
// execute the defined bindings
Backbone.ModelBindings.call(this);
}
});
model = new SomeModel();
view = new SomeView({model: model});
model.set({name: "some name"});
In this example, when model.set is called to set the name, "some name" will appear
in the #name input field. Similarly, when the #name input field is changed, the
value entered into that field will be sent to the model's name attribute.
The following form input types are supported:
- text
- password
- textarea
- checkbox
- select
- radio button groups
Radio buttons are group are assumed to be grouped by the name attribute of the
radio button items.
Select boxes will populate 2 separate fields into the model that they are bound to.
The standard #fieldid will be populated with the selected value. An additional
{#fieldid}_text will be populated with the text from the selected item. For example,
a selected option of
<select id='company'>
<option value="foo_bar">Foo Bar Widgets, Inc.</option>
...
</select>
will populate the company attribute of the model with "foo_bar", and will populate
the company_text attribute of the model with "Foo Bar Widgets, Inc."
There is no support for hidden fields at the moment, because there is no 'change' event that jQuery can listen to on a hidden field.
Non-conventional, bi-directional binding between your form input and your model.
Add formBindings document to you view, to specify the bindings you want to use. The format is
the same as the Backbone view events
SomeView = Backbone.View.extend({
formBindings: {
"#someInput": "a_field"
}
});
The input element must be settable via the jQuery val method. You can specify any valid jQuery
event to monitor for a change, though.
Now when you type into the form input, your model's fields will be updated automatically. When your model's fields are changed, the form input will update automatically. And, when you render the view, the field will be populated with the value that exists in the model at rendering time.
Model -> HTML element binding for your model's field value changes.
Add an 'htmlBindings' document to your view, to specify the bindings you want to use. The format is to list the html element selector on the left, and the model's field on the right.
SomeView = Backbone.View.extend({
htmlBindings: {
"#someElement": "a_field"
}
});
Now when the model's a_field is changed, the html element #someElement will have it's contents
replaced by the value that is entered into the model's a_field field.
Note: htmlBindings is experimental as I don't have an actual use for it right now. I put it in because it was easy and it might inspire some other ideas at some point.
The convention based bindings are pluggable. Each of the existing form input types can have it's convention replaced and you can add your own conventions for input types not currently handled, etc.
To replace a convention entirely, you need to supply a json document that has two pieces of
information: a jQuery selector string and an object with a bind method. Place the convention
in the Backbone.ModelBinding.Conventions and it will be picked up and executed. The bind
method receives three parameters: the jQuery selector you specified, the Backbone view, and
the model being bound.
You can replace the handler of an existing convention. For example, this will set the
value of a textbox called #name to some text, instead of doing any real binding.
var nameSettingsHandler = {
bind: function(selector, view, model){
view.$("#name").val("a custom convention supplied this name");
}
};
Backbone.ModelBinding.Conventions.text.handler = nameSettingsHandler;
You can also create your own conventions that do just about anything you want. Here's an example
that modifies the contents of <p> tags:
var PConvention = {
selector: "p",
handler: {
bind: function(selector, view, model){
view.$(selector).each(function(index){
var name = model.get("name");
$(this).html(name);
});
}
}
};
Backbone.ModelBinding.Conventions.paragraphs = PConvention;
This example will find all <p> tags in the view and render the name attribute from the model
into that paragraph, replacing all other text. Note that the name of the convention is set to
paragraphs when added to the conventions. This name did not exist prior to this assignment, so
the convention was added. If you assign a convention to an existing name, you will replace that
convention.
The list of existing conventions includes:
- text
- password
- radio
- checkbox
- select
- textarea
For fully functional, bi-directional binding convention examples, check out the source code
to Backbone.ModelBinding in the backbone.modelbinding.js file.
backbone.modelbinding is still in the early stages and has limited functionality. Although functionality is being built with unit tests, in a test-first manner, there is no guarantee that it will work. At all. Use at your own risk and be sure it works the way you expect before deploying to any production environment.
Copyright (c) 2011 Derick Bailey, Muted Solutions, LLC
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.