Or: that framework frameworks best which frameworks least.

The last couple of years have seen a big shift of UI code from the server to the client. JavaScript is growing up, the browser is the new OS, and the major browser vendors have finally learned to talk out their disagreements like responsible adults. Well, mostly. Eventually. Given enough time.

A while ago, at the company I work for, we decided to upgrade the design of our venerable customer portal and move some of the more interactive UI components from our webservers to the client. And since we were really, really serious about it: no quagmire of jQuery plugins and assorted click-handlers. This was the year of the JavaScript framework after all. It was time to build us some maintainable, testable, enterprise-level JS components.

So, a JS framework we would have. But which one? I was tasked to take a look at all the options and select the one most suitable to our needs. And we certainly had a lot of options. It seems everybody and their dog are writing JS application frameworks these days. Some are even maintained by such well-known companies as Facebook and Google. Time to go out exploring, meet the locals, and see the sights.

I started by making a list of candidates. Then I began building proofs of concept, recreating a very limited example of our customer portal using the ideas and idioms of each framework. I continued doing this for a couple of weeks. After that, I took stock of the code I had written for each framework, and what my experience had been writing it.

Here’s what I learned.

Introducing…

The most well-known JavaScript framework is Google’s AngularJS. We had previously used Angular to build our customer checkout process. Our experiences with the framework were mixed. Certainly Angular made good on the promise of a JS application framework. We were able to turn out a complete multi-step checkout process without having to dive into the nitty-gritty details of DOM manipulation (often).

But Angular is a bit… particular in its conventions and interpretation of the MVC pattern. It took a while to figure out which piece goes where, which isn’t ideal when several people are working on an application simultaneously. Besides, Angular has long been plagued by performance issues. We had to do some tuning, rethink some of our code to get it to start working quickly after page load.

For a while now, a large team of developers has been working on Angular 2. Don’t let the name fool you: this is a completely new framework with new syntax and new ideas. The first beta came out just as we started considering it as a candidate (it has since been released). There’s talk of a pipeline for completely pre-compiling your templates, isomorphic app support, native app support - you name it. Angular 2 seems all set to fulfil the promise developers have been chasing after since time immemorial: code once, run everywhere.

In the blue corner, coming in at a mere 43KB minified, from Facebook, it’s… React. React is a view engine, not a complete application framework. You’ll have to add additional libraries for e.g. validation, or communicating with the backend. React focuses on giving excellent performance and being easy to debug. When it came out, it blew the old Angular, and most other frameworks, away in benchmarks. Things have evened out a bit since then but React is still among the fastest JS frameworks.

React came with a lot of ideas that have since been copied by many other frameworks. For one, it popularized reactive programming in JS frameworks. In React, this means that views are purely a mapping of your application state to HTML elements. There’s no support for two-way databinding. Every user interaction, server-response and event must manipulate the application state in predictable ways. After that React recomputes an in-memory representation called the Virtual DOM and manipulates only those actual DOM elements that have changed since the last update.

And then there’s the most popular JavaScript framework you’ve never heard of: Aurelia. It was created by experienced framework developer Rob Eisenberg, who was part of the development team for Angular 2 for a few months before they went their separate ways. It’s built with the very newest JavaScript standards, some of which haven’t even been finalised yet. But it can be transpiled to plain old ES5 JavaScript so simple that even your granny’s IE9 can run it.

Aurelia and Ember are also among the few JavaScript frameworks to be a core product of their parent companies - Angular and React are not officially endorsed by Google or Facebook. Which means you can be reasonably sure that the framework developers won’t introduce breaking changes without warning, and that the code you write today will still be supported years from now.

I also had a go at an Ember proof of concept, but found it difficult to develop only small UI components rather than a full client-side application. Ember is strongly opionated, and its tools and tutorials assume you’re working on a brand new application. Our company was working with legacy code, a lot of it, and it will be a long time before we’re ready to move to a single-page application. Besides, by this time I’d been working on this for a few weeks, and my conclusion was pretty clear.

And the winner is…

Aurelia, by a mile. Sure, it’s still rather new, sure it doesn’t have as big a community as some of the other frameworks (though the core developers are very dedicated and respond quickly to questions). But there is one thing Aurelia offers that no other framework does: when I’m writing my components, I’m writing plain old JavaScript and plain old HTML. …well, TypeScript and custom HTML tags, but you get the idea.

While developing with Angular 2, I was very clearly writing Angular code (the Angular template syntax isn’t even standards-compliant HTML, strictly speaking). React invented its own template language - JSX - which isn’t supported by my current tooling and probable won’t be for the foreseeable future.

By contrast, take a look at this:

export class MyComponent { constructor() { this.numberOfClicks = 0; } handleClick(e) { console.log('you clicked: ' + e.target); console.log('number of clicks: ' + ++this.numberOfClicks); } }

and the associated template:

<template> <a click.trigger="handleClick($event)"> This is a component. Watch your console when you click it. </a> </template>

If somebody had asked me to write out my ideal component code, it would probably have looked a lot like this. Put your template in my-component.html and your code in my-component.js and Aurelia will wire everything up, no config or glue-code required. It works out of the box. Anywhere I put <my-component></my-component> , Aurelia will render my component.

This is portable code. I know it when I see it. If Aurelia folds tomorrow (which I doubt) and I have to move everything I’ve built over to another framework, I know it will work. I’ll have to move some decorators around, change some calls to framework APIs, but the UI and business logic that I’ve written are plain code and will work with any halfway decent framework.

More than that: it’s elegant. In fact, the code I’ve written since we’ve decided on Aurelia and started creating real UI components has been some of the most elegant code I’ve ever written. I’d say it reads like Shakespeare, except I think Shakespeare will be harder for the average English-speaker to understand than some of the code I’ve pushed to our repository over the last few weeks.

There are still some rough edges here and there. The documentation of some of the more advanced features still leaves a lot to be desired. But I’m willing to forgive a lot. Aurelia’s still young, after all. Besides: I’ve had nothing but earnest and helpful feedback on any issue I’ve opened on Github or question I’ve asked on StackOverflow. And I’ve learned more about new and upcoming JavaScript standards in the last few weeks than in the past few years (async functions FTW!).

So my advice to you, based on experience, is to ignore the big brand frameworks and get yourself familiar with the framework that gets out of your way and lets you get on with it. Go try it out and let me know what you think: I’d love to hear about your experiences.