JavaScript for Line of Business Applications

In my day job, I work on appear.in, a video chat service built with AngularJS and WebRTC. Recently, our application has become more complex, and our HTML templates ended up having a lot of state in them. We could no longer just use unit testing to verify our application logic, we also needed to test the state in our templates.

For our unit testing, we landed on using Jasmine and Karma, and this has worked fairly well for us. So when we wanted to test our templates, we wanted to use the same tools.

Ext JS 4.0 provides a number of ways for custom components to render their HTML content for display:

autoEl, html, tpl/data, renderTpl/renderData

As I have been learning Ext JS, I have often struggled with knowing which technique is the correct one in a given situation. Here I will briefly discuss the different ways of specifying content, followed by some thoughts on when you might want to use them.

OJ is a JavaScript library with the goal to make objects that create and live edit the web.

When making a website you have to keep in mind HTML, CSS, and JavaScript code. In OJ, all three parts are unified into objects. OJ can render to HTML and CSS as well as bind JavaScript events.

The benefit is that OJ objects have no dependencies. There is no need to read the docs to be sure the HTML is correct, or see if the CSS is included. Everything just works.

* Abstracts the web into view objects that create and change websites
* Unifies templating of HTML, CSS and JS
* A library written entirely in JavaScript
* Backbone support built-in with two-way model and collection binding
* Includes the simple smart objects: List, Table, Button, and form elements
* A growing collection of plugins: VimeoVideo, AceEditor, and more!
* DOM manipulation client-side
* HTML and CSS creation server-side
* Node server-side support (in progress)

My least favourite part in Angular is their templating syntax. Angular uses plain HTML with custom DOM attributes attributes for control flow (ng-hide, ng-show, ng-repeat). Whereas Ember uses Handlebars which supports more familiar control flow statements (if, else, each). Personally I prefer the Ember approach as it’s similar to most templating languages I have used (erb, haml, etc) and it’s easier for my CPU (aka brain) to scan and parse.

Lets look at a couple of examples.

So you're using the same language on the browser and the server. Great!

You can get the benefits of fast initial page loads server-side that are easily indexed by search engines while simultaneously rendering realtime and on-demand content browser-side for a rich, responsive user experience!

This sounds really great, but now you might be thinking:

* How do I load the shared code in both environments without making a mess?
* How can I load files like html or templates in a way that works in both node and the browser?
* How do I render the data?
* How should I route the data where it needs to go?
These questions are not obvious and there are many ways to answer them! The rest of this article is some answers that I've discovered or built that work well together.

Rivets.js is completely agnostic about your model / controller layer and works well with existing libraries that employ an event-driven model such as Backbone.js and Stapes.js. It ships with a built-in adapter for subscribing to plain JS objects using ES5 natives, however this can be replaced with a Watch.JS adapter or an Object.observe adapter.

From the event handlers to the template delimiters, the attribute prefixes to the preloading of data. It's all configurable and tunable at the application level as well as locally to individual views.

I really enjoy using block-style template inheritance in Jade and Handlebars. From my understanding, this pattern was popularized by Django.

AngularJS rocks, but it relies on template inclusion to define layouts. This means the a layout context is spread across several templates. With block-style template inheritance, layouts are defined within a single template. Moreover, multiple layouts can be DRY’ed up with inheritance.

So I set out to build angular-blocks, an AngularJS module, to support template blocks.

Hungry for some file templates to get you started in the morning? Well now you can fill up on a set of web template packs for Visual Studio 2012 and 2013. SideWaffle is an open source project that creates a Visual Studio extension containing a set of file templates you can use for web projects.
SideWaffle currently has several templates including 10 I contributed for Angular, Durandal, and creating a JavaScript IIFE. One of the best parts is that SideWaffle will be frequently updated with new and useful templates (they do check for high quality templates). I expect that in the near term we’ll see a lot of additions.
* Angular Controller (using Controller As syntax)
* Angular Controller (using $scope)
* Angular Directive (creates a skeleton for a directive)
* Angular Factory (great for data, logging, and other services)
* Angular Module (sets up a module)
* Durandal ViewModel
* Durandal Service
* Durandal main.js (common creation syntax for kicking off Durandal)
* JavaScript IIFE (Basic IIFE using vanilla.js)
I use the Angular templates in my upcoming course at Pluralsight on using Angular and Breeze to build a powerful SPA.

Well, after getting the basics to work I decided to clean up the mess that was quickly becoming of the HTML and found the wonderful HandlebarsAssets gem that promises to compile Handlebars down to JavaScript and serve it through the Rails 3.1+ asset pipeline. After doing so I can say with confidence I managed to hit every single stumbling block along the way so I decided to write down where I went wrong. Hopefully this helps some other poor soul before he has to dive deep into the bowels of Ember like I had to :).

In this post I will introduce the concept of templating. It is very likely you have already used some template engine. As a result I will go through the fundamentals quickly and then focus on a set of JavaScript ones.

You will see various approaches. There is no single right way to deal with it and sometimes it comes down to personal tastes. In this case I'll focus on just a few engines, namely Mustache, Jade andTransparency. You can find a full list of engines at our service in case you can see the available options.