backbone.layoutmanager

Created by Tim Branyen @tbranyen with contributions from @nedcampion

Provides a logical structure for assembling layouts with Backbone Views. Designed to be adaptive and configurable for painless integration.

Depends on Underscore, Backbone and jQuery. You can swap out the jQuery dependency completely with a custom configuration.

Tutorials and Screencasts

Initial Screencast

Download & Include

Development is fully commented source, Production is minified and stripped of all comments except for license/credits.

Include in your application after jQuery, Underscore, and Backbone have been included.

<script src="/js/jquery.js"></script>
<script src="/js/underscore.js"></script>
<script src="/js/backbone.js"></script>

<script src="/js/backbone.layoutmanager.js"></script>

Usage

This example renders a View into a template which is injected into a layout.

Create and render a layout

This code typically resides in a route callback. If you want to provide a custom object for your template engine to the layout, use the serialize property.

// Create a new layout using the #main template.
var main = new Backbone.LayoutManager({
  template: "#main-layout",

  // In the secondary column, put a new Login View.
  views: {
    ".secondary": new LoginView()
  }
});

// Render into <body>.
main.render(function(el) {
  $("body").html(el);
});

Views may also be alternatively defined later:

main.view(".header", new HeaderView);
main.view(".footer", new FooterView);

Use the above syntax to change out views at a later time as well, remember to call the View's render method after swapping out to have it displayed.

Nested Views

You may have a situation where a View is defined that encapsulates other nested Views. In these cases you should use nested views inside your LayoutManager View assignments.

Check out this example to see how easy this is:

var main = new Backbone.LayoutManager({
  template: "#some-layout",

  views: {
    ".partial": new PartialView({
      views: {
        ".inner": new InnerView()
      }
    })
  }
});

You can nest Views infinitely.

Structuring a View

Each View needs to have a template associated, via the template property. This name by default is a jQuery selector, but if you have a custom configuration this could potentially be a filename or JST function name.

var LoginView = Backbone.View.extend({
  // Tell LayoutManager what template to associate with this View.
  template: "#login-template",

  // The render function will be called internally by LayoutManager.
  render: function(layout) {
    // Wrap the layout with this View and call render.
    return layout(this).render();
  }
});

Optionally, you can extend from LayoutManager.View and omit the render method. If you need to do custom logic in render, you should use the other pattern above.

var LoginView = Backbone.LayoutManager.View.extend({
  template: "#login-template"
});

Re-rendering Views

Instead of re-rendering the entire layout after data in a single View changes, you can simply call render() on the View and it will automatically update the DOM. You cannot bind to the initial render reference, like so

Assume that you have a model that when changed, causes a redraw.

var MyView = Backbone.LayoutManager.View.extend({
  initialize: function() {
    this.model.bind("change", this.render, this);
  }
});

You must use this syntax instead, calling it from a function:

var MyView = Backbone.LayoutManager.View.extend({
  initialize: function() {
    this.model.bind("change", function() {
      this.render();
    }, this);
  }
});

This necessity may be alleviated in a future version.

Working with context

Template engines bind data to a template. The term context refers to the data object passed.

LayoutManager will look for a serialize method or object automatically:

var LoginView = Backbone.LayoutManager.View.extend({
  template: "#login-template",

  // Provide data to the template
  serialize: function() {
    return this.model.toJSON();
  }
});

You can also pass the context object inside the render method:

var LoginView = Backbone.View.extend({
  template: "#login-template",

  render: function(layout) {
    // Provide data to the template
    return layout(this).render(this.model.toJSON());
  }
});

Defining the layout and template

These example templates are defined using a common pattern which leverages how browsers treat <script></script> tags with custom type attributes.

This is how LayoutManager expects templates to be defined by default (using script tags).

Main layout

<script id="main-layout" type="layout">
  <section class="content twelve columns"></section>

  <!-- Template below will be injected here -->
  <aside class="secondary four columns"></aside>
</script>

Login template

<script id="login-template" type="template">
  <form class="login">
    <p><label for="user">Username</label><input type="text" name="user"></p>
    <p><label for="pass">Password</label><input type="text" name="pass"></p>
    <p><input class="loginBtn" type="submit" value="Login"></p>
  </form>
</script>

Using jQuery Plugins

Attaching jQuery plugins should happen inside the render methods. You can attach at either the layout render or the view render. To attach in the layout render:

main.render(function(el) {
  $(el).find(".some-element").somePlugin();
  $(".container").html(el);
});

In the above example its entirely possible the elements are not in the DOM yet. This happens when you fetch templates asynchronously. Using the following method, elements will be added into the DOM. To attach in the layout render, you will need to override the render method like so:

render: function(layout) {
  return layout(this).render().then(function(el) {
    $(el).find(".some-element").somePlugin();
  });
}

This is a very cool example of the power in using deferreds. =)

Configuration

Overriding LayoutManager options has been designed to work just like Backbone.sync. You can override at a global level using LayoutManager.configure or you can specify when instantiating a LayoutManager instance.

Global level

Lets say you wanted to use Handlebars for templating in all your Views.

Backbone.LayoutManager.configure({
  // Override render to use Handlebars
  render: function(template, context) {
    return Handlebars.compile(template)(context);
  }
});

Instance level

In this specific layout, define custom prefixed paths for template paths.

var main = new Backbone.LayoutManager({
  template: "#main",

  // Custom paths for this layout
  paths: {
    template: "/assets/templates/"
  }
});

Defaults

Paths: An empty object. Two valid property names: template and layout.

paths: {}

Deferred: Uses jQuery deferreds for internal operation, this may be overridden to use a different Promises/A compliant deferred.

deferred: function() {
  return $.Deferred();
}

Fetch: Uses jQuery to find a selector and returns its innerHTML content.

fetch: function(path) {
  return $(path).html();
}

Partial: Uses jQuery to find the View's location and inserts the rendered element there.

partial: function(layout, name, template) {
  $(layout).find(name).html(template);
}

Render: Renders a template with Underscore.

render: function(template, context) {
  return _.template(template)(context);
}

Asynchronous & Synchronous fetching

The fetch method is overridden to get the contents of layouts and templates. If you can instantly get the contents (DOM/JST) you can return the contents inside the function.

Backbone.LayoutManager.configure({
  fetch: function(name) {
    return $("script#" + name).html();
  }
});

If you need to fetch the contents asynchronously, you will need to put the method into "asynchronous mode". To do this, assign this.async() to a variable and call that variable with the contents when you are done.

Backbone.LayoutManager.configure({
  fetch: function(name) {
    var done = this.async();

    $.get(name, function(contents) {
      done(contents);
    });
  }
});

Sample Configurations

You may need to combine a mix of Engines and Transports to integrate.

Engines (Mustache, Handlebars, etc.)

Custom templating engines can be used by overriding render.

Underscore

No configuration necessary for this engine.

Mustache

Backbone.LayoutManager.configure({
  render: function(template, context) {
    return Mustache.to_html(template, context);
  }
});

Handlebars

Backbone.LayoutManager.configure({
  render: function(template, context) {
    return Handlebars.compile(template)(context);
  }
});

Transports (DOM, AJAX, etc.)

You can swap out how templates are loaded by overriding fetch.

DOM

No configuration necessary for this transport.

AJAX

Backbone.LayoutManager.configure({
  fetch: function(path) {
    var done = this.async();

    $.get(path, function(contents) {
      done(contents);
    });
  }
});

Using an Engine and Transport Override for JST

Whatever you decide to return as a template in fetch, can be used in the render method.

Backbone.LayoutManager.configure({
  fetch: function(name) {
    return window.JST[name];
  },

  render: function(template, context) {
    return template(context);
  }
});

TrisMcC/backbone.layoutmanager