Let’s Code: Test-Driven JavaScript

James Shore presents a fascinating screencast
on rigorous, professional JavaScript development

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Latest Live Episodes

  1. Don’t Repeat Your CSS

    Wed, 7 Oct

    We continue factoring out CSS common to our buttons. Our two buttons have some significant differences, particularly with regard to positioning and colors, but we end up with a nice clean solution... and delete a bunch of duplicated CSS along the way.

  2. Challenges of CSS Reuse

    Mon, 5 Oct

    It’s time to refactor the CSS for our clear button. This one is particularly interesting because it’s simultaneously an element inside our drawing area and a type of button. There’s an opportunity here to factor out the commonalities between the two buttons... but how can we do it cleanly?

  3. Test-Driven Elements

    Wed, 30 Sep

    We finish unit testing our drawing area's CSS arrow and canvas elements. Figuring out to test-drive block elements has been a challenge, but by the end of the episode, we’ve got it under control.

Latest Specials

  1. The Build Step

    Fri, 2 Oct

    In order for our modules to work in production, we need to run a third-party tool on them first. (In our case, Browserify.) This is called a “build step.” We walk through the process manually, then update our automated build to do it automatically.

  2. Modules in Production

    Fri, 25 Sep

    We can use CommonJS modules to organize our test files, but we don’t yet have the same ability in our production code. When we try, the application just crashes. We introduce Browserify and Webpack, two popular tools for supporting CommonJS in production, then demonstrate how to install and use Browserify.

  3. Modular Tests

    Fri, 18 Sep

    We start a new chapter looking at modularity: splitting your JavaScript code across multiple files so it’s better organized and easier to understand. We use the CommonJS Modules format to split our example test into a “test” file and a “production” file. Then we make it work with our tests by installing the karma-commonjs plugin.

An in-depth screencast about
Test-Driven JavaScript

You've taught me a lot this past year and have
been better than a teacher, a true mentor.
Jason Weden
I’m completely new to TDD and this is by far
the most comprehensive TDD for JS... your videos are
a breath of fresh air!
Adam Brodzinski
This is a gold mine... This will help a lot in my day job.
Timothy Myers
Love what you're doing. It's helped out our
team tremendously here at Sevenly.
Scott Corgan
I’m delighted with LCJ. It’s interesting and informative, and the
candid way you think aloud makes it personal and engaging.
You’ve done a terrific job.
Crispin Bennett

JavaScript Needs Test-Driven Development

If you’ve programmed in JavaScript, you know that it’s an… interesting… language. Don’t get me wrong: I love JavaScript. I love its first-class functions, the intensive VM competition among browser makers, and how it makes the web come alive. It definitely has its good parts.

It also has some not-so-good parts. Whether it’s browser DOMs, automatic semicolon insertion, or an object model with a split personality, everyone’s had some part of JavaScript bite them in the butt at some point. That’s why using test-driven development is so important.

What is Test-Driven Development?

Test-driven development (TDD) is a technique for ensuring that your code does what you think it does. It’s particularly relevant for JavaScript, with its cross-browser incompatibilities and hidden gotchas. With TDD, you express your intentions twice: once as a test, and once as production code. If the two approaches don’t match, your tests fail, and you’ve caught a bug.

TDD is a great way of catching the majority of programming errors. It’s not perfect, of course—in particular, it can’t tell you when your assumptions are wrong—but it’s very good at catching the kinds of bugs JavaScript is prone to.

Who am I?

I’m James Shore. I’ve been building applications using test-driven development and other Agile techniques for over 15 years. I’m a recipient of the Agile Alliance’s Gordon Pask Award for Contributions to Agile Practice and I wrote a book called The Art of Agile Development.

What You Get

This screencast series focuses on rigorous, professional web development. That means test-driven development, of course, and also techniques such as build automation, continuous integration, refactoring, and evolutionary design. We test against multiple browsers and platforms, including iOS, and we use Node.js on the server.

All videos are DRM-free, available for streaming or download, and all source code is included.

The Videos

The series consists of four main channels. The “Recorded Live” channel focuses on real-world development, warts and all. It’s meant for experienced programmers.

If you’re a new developer, the “How To” channel is for you. It’s meant for beginners who have recently learned to program and are ready to start their professional career.

The “Lessons Learned” channel provides concise reviews of key topics, such as continuous integration, test-driven development, and build automation. It’s great for review and reference.

Advanced programmers will enjoy “The Lab”, our channel focused on exploring new tools and ideas.

Release Schedule

New videos are published every week. At the time of this writing, a new “Recorded Live” episode is released every Monday and Wednesday, and a new “How To” episode is released every Friday.

When the current “How To” season finishes, we will probably return releasing a new “Lessons Learned” or “The Lab” episode on the first Friday of every month.

“Recorded Live” and “How To” episodes are about 15 minutes long. “Lessons Learned” videos are typically about 15-30 minutes long, and episodes of “The Lab” tend to be about an hour.

I have learned so much more than I expected.
I really enjoy your approach to screencasting and
wish the series wouldn’t end some day.