Re-Learning Backbone.js – View Render

In this post we learn about different ways to render HTML using Backbone.js view and Underscore templates.

A Backbone view should include a render function. The render function should have the responsibility of manipulating the view’s el property. The el property is then used to update the DOM.

This post builds on the following posts:
Re-Learning Backbone.js – View Basics
Re-Learning Backbone.js – Templates (Underscore)
Re-Learning Backbone.js – Models
 

Here are a couple of quotes about Backbone.js Views:

“Backbone views are almost more convention than they are code — they don’t determine anything about your HTML or CSS for you, and can be used with any JavaScript templating library. The general idea is to organize your interface into logical views, backed by models, each of which can be updated independently when the model changes, without having to redraw the page. Instead of digging into a JSON object, looking up an element in the DOM, and updating the HTML by hand, you can bind your view’s render function to the model’s “change” event — and now everywhere that model data is displayed in the UI, it is always immediately up to date.” http://backbonejs.org/#View

“At a technical level, a Backbone view is simply a JavaScript object that manages a specific DOM element and its descendants.” http://aaronhardy.com/javascript/javascript-architecture-backbone-js-views/

In this first example we are going to add some text to a DOM div element.


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Re-Learning Backbone.js – View Basics

There is probably more confusion with Backbone.js Views than with other features of Backbone. In this post I’m going to describe some basic features of Backbone Views. Also, In this post we will not be rendering any HTML, but I believe the concepts that you will learn will provide the bedrock for understanding Views better.

The end goal of a Backbone View is to represents an object in the DOM. Many times a view will be created that will manipulate an object that represents an element that is not originally assigned to the DOM. At some point the view object will be assigned to the DOM element and displayed.

A view usually builds up an element and adds it to the DOM. Here’s an example of what a view represents.

This element would be built by the Backbone view and then added to the DOM.

It’s important to understand that once a view is added to the DOM, the view is still aware of that element in the DOM and can manage that element. So if events occur on the DOM element, such as click or keyUp, the view can be notified of these changes and take action. Also if a view references a model and the model changes, the view can be automatically updated and in-turn the DOM element will be updated to reflect the changes in the model.

“At a technical level, a Backbone view is simply a JavaScript object that manages a specific DOM element and its descendants.” http://aaronhardy.com/javascript/javascript-architecture-backbone-js-views/

“How does Backbone relate to “traditional” MVC?
Different implementations of the Model-View-Controller pattern tend to disagree about the definition of a controller. If it helps any, in Backbone, the View class can also be thought of as a kind of controller, dispatching events that originate from the UI, with the HTML template serving as the true view. We call it a View because it represents a logical chunk of UI, responsible for the contents of a single DOM element.”
http://backbonejs.org/#FAQ-mvc

I don’t want to overwhelm you with a lot of content, so I’m going to take very small step to explain some core features of Backbone views. Even though it’s our end goal, in these examples we will not assign a view to a DOM element. Everything will be logged to the browser console.


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Re-Learning Backbone.js – Templates (Underscore)

Even though templates are not part of Backbone.js, I believe it’s critical to have a basic understanding of templates. Templates are a core component that will be used with Backbone.js Views.

Templates will help us separate code from the HTML markup. When MVC is discussed in regards to server side (Ruby on Rails, ASP.NET MVC) the “V” is for view. Views are implemented different in Backbone than in most server side technologies. On the server side, views should be extremely dumb and very little logic if any should be include.

Backbone.js has a key object called View. The Backbone.js View does not resemble server side views. Backbone.js Views are not dumb and they do have logic. Some people have described Backbone.js Views as being more similar to Controllers on server side. I believe that templates on the client (JavaScript) side work more like the views on the server side. It’s definitely a mind shift when moving from a server MVC mindset to a client side MVC mindset. Hopefully this will make the transition easier.

I want to keep this as simple as possible. We will take very small steps to help you learn about templates. Only 2 JavaScript libraries will be needed, jQuery and Underscore. We will not be using the Backbone.js library. There are many options for templating, but we will use the built in option that Underscore provides. In case you didn’t know, Backbone.js has a dependency on Underscore. This is why we are using Underscore’s template engine, but other template engines can be substituted for the Underscore template engine.

Very, Very Simple Template

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Re-Learning Backbone.js – Models

Over the past few days I’ve started to re-learn Backbone.js. It’s been a good while since I have worked with it. One of the many resource that I used during this endeavor is the post that I created January of this year. Understanding Backbone.js – Simple Example

Since I’m re-educating myself on Backbone.js, I thought this would be a good opportunity to Blog about the process I’m going through while re-learn Backbone.js again. In this post I will present the concept of Backbone.js Model.

So here I go again.

Based on past experience, I believe creating an application on Backbone.js there’s are few key concepts that should be understood: Model, View, Collection, Template and Router.

The first thing we are going to do is create a Movie class and instantiate an instance of the movie. Nothing fancy, this should be very simple. This Movie class will be based on a Backbone.js Model. JavaScript does not support classes, but here we will simulate a class.

Movie Sample 1

The code above is creating a Movie class from Backbone.Model.Extend. When an object is created from the Movie class the intialize function should be called and the message “Movie Model Created” should be written to the console.

If you load this page in a web browser, I’m using chrome, the results should be displayed in the console.

There is a problem here, everything is a global variable. Since we will be creating many Models, Views, Collections and templates, lets create a place to organize these structures.


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Understanding Backbone.js – Simple Example

I’m by no means an expert in Backbone.js.  I created this post because I had difficulty understanding backbone, and I hope that the information that I provide will help others grasp Backbone.js a little faster.  This post is directed to individuals who understand the concepts of Backbone.js, but are having a difficult time implementing a simple solution.

This post provides a simple example on Backbone.js Routers, Models and Collections and Views.  I’m going to try to make this example extremely simple. But also show key Backbone.js concepts

I’m probably not the best writer.  It would take me days, if I were to validate all the grammar, spelling and such.  So I’m just going to try to get it done.  Even though the grammar and such may not be perfect, the technical parts of the article should be correct.  I hope you enjoy.

A few months after writting this post, my priorites and technology direction changed. For probably 6 months I did little work with Backbone.js. When I came back to Backbone.js in November, I was a little lost. I had to become familar with the technology once again. I thought it would be a good opportunity to write about Backbone.js basics. Here are posts where I describe the basics of Backbone.js.

This post will be based on a contrived idea of displaying a list of movies at a theater.
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