Why Just JavaScript Should Be Required Reading for Every Dev

A few years ago I saw a tweet recommending a paid course called Just JavaScript, by Dan Abramov and Maggie Appleton. I had just finished a fullstack bootcamp, and I figured I’d give it a shot. It ended up being one of the most useful things I’ve ever paid for as a developer, and I still recommend it to pretty much anyone who asks me how to get better at JavaScript.

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The problem with how most of us learn JS

Most tutorials, courses, and bootcamps teach you how to use JavaScript: how to declare a variable, which array method does what, how to write a function. What almost none of them teach is what’s actually happening underneath when you do those things.

That gap doesn’t really show up while you’re learning — it shows up later, when you hit a bug that makes no sense, or you can’t explain why two objects that look identical aren’t equal, or why a variable suddenly has a different value than you expected depending on whether you used var, let, or const. At that point it stops feeling like “I don’t know this yet” and starts feeling like “this language is a black box and I just have to memorize its quirks.”

That was exactly where I was after finishing my diploma. I knew how to use JavaScript. I didn’t know how it worked. And that made debugging — and even working with AI tools that generate code — a lot harder than it needed to be, because I couldn’t reason about what was going on, I could only react to error messages.

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What the course actually changes

Just JavaScript doesn’t teach you syntax. It builds a mental model of the language from the ground up — values, references, scope, equality — and once that model clicks, a lot of things that used to feel like arbitrary rules suddenly make sense on their own.

The chapters that hit hardest for me were Mental Models, Primitive Values, and Studying from the Inside. Those are the ones that reframe how you think about JavaScript at a fundamental level, not just how you write it.

It’s also worth mentioning the production value: the storytelling and illustrations (by Maggie Appleton) make the whole thing genuinely enjoyable to go through, which is rare for something this technical. It doesn’t read like documentation — it reads like a well-paced story that happens to teach you the internals of the language.

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Who I’d recommend it to

Honestly, two groups:

• Beginners, because it gives you the right foundation before bad habits and black-box thinking set in.
• Developers with some experience who’ve had that moment of “wait, I use this every day and I’m not totally sure why it works the way it does.” If that sentence resonates, this course is for you.

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A few things worth knowing

It’s $42, and it’s yours for life — no subscription. Given how much it changes the way you reason about the language, that’s a pretty easy decision.

It’s not a long course, and it’s not meant to replace learning frameworks, tooling, or any of the practical stuff. It’s meant to fill in the part that most resources skip entirely: what’s actually happening when your code runs.

If you’ve ever felt like JavaScript is something you use rather than something you understand, this is the fix.