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The Tricky Parts of JavaScript

A short, focused Pro course from Zack Wilson on the JavaScript concepts that trip people up: closures, this, hoisting, and type coercion, in under an hour.

Quick answer​

The Tricky Parts of JavaScript is a 59-minute, Pro-tier, intermediate course taught by Zack Wilson (PortEXE). It zeroes in on the language behaviors that confuse self-taught developers, like closures, the this keyword, hoisting, and coercion. It is best used as a targeted top-up after a beginner course, not as your first encounter with JavaScript. If those four topics make you uneasy, this is an efficient hour.

Is it worth your time?​

If you can build small JavaScript apps but still get surprised when this points somewhere unexpected or a closure captures a value you did not mean, this is an hour well spent. It is narrow on purpose, and that focus is the value: no padding, just the concepts that quietly cause bugs.

The honest caveat is that it assumes you already know the basics. It is not a teaching-from-zero course, and at 20 lessons it is a supplement, not a curriculum. If you have never written JavaScript, this will feel like answers to questions you have not asked yet.

What you'll learn​

The course is built as a set of focused lessons and challenges around JavaScript's most misunderstood mechanics. Expect closures and lexical scope, the rules that decide what this refers to, hoisting of variables and functions, and the type coercion behind JavaScript's surprising equality comparisons. Each is the kind of topic that beginner courses gloss over and interviewers love to probe.

Because it is short and concept-driven, it pairs well with practice elsewhere. Think of it as the explanation layer that makes your existing JavaScript click.

Who it's for, and who should skip it​

It fits developers who have finished a beginner course like Learn JavaScript and keep hitting confusing behavior, or anyone prepping for interviews where these topics come up constantly.

Skip it if you are a complete beginner; do Learn JavaScript first. Also skip it if you want broad coverage rather than a targeted fix, where Advanced JavaScript is the fuller course.

Prerequisites​

A working knowledge of JavaScript basics: variables, functions, and scope. You do not need to be advanced, but you should have written some JavaScript before this will make sense.

Where it fits​

The Tricky Parts of JavaScript is a supplemental stop on the Frontend Developer Path and the Fullstack Developer Path, best taken after the JavaScript fundamentals and before interview prep.

Free or Pro​

This is a Pro course, so it requires a Scrimba subscription. Pro also covers the full career paths, the coding challenges, the Discord, and certificates. See current plans for what Pro costs in your region.

Strengths and limits​

What it does well: it is short, focused, and targets the exact concepts that cause subtle bugs and interview stumbles. Zack Wilson keeps it concrete rather than academic.

Where it is limited: it is a supplement, not a course you can start from zero with, the 20-lesson runtime is genuinely brief, and it assumes you bring the basics yourself.

View The Tricky Parts of JavaScript on Scrimba (opens in a new tab)

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