JavaScript: The Hard Parts, v2 vs CSS Grid and Flexbox, v2

Goes deep on the JavaScript runtime model — thread of execution, the call stack, closure, the event loop, Promises and prototypes/classes — across roughly 6.5 hours. Reviewers consistently say it explains how JavaScript works "under the hood" rather than just syntax.

Will Sentance (Codesmith founder) is the most-praised element. Learners cite his blackboard diagrams, the "backpack" analogy for closure, and a Socratic, audience-paced delivery. The same intense, repetitive style is the one thing a minority find tiring.

Requires a $39/month Frontend Masters subscription rather than a one-time purchase — strong value if you use the wider catalog, weaker if you only want this one course. The course is included in the standard subscription.

This is a conceptual, exercise-and-whiteboard course, not a project build. There is no portfolio-worthy capstone, which some learners miss. The exercises are effective for drilling mental models but produce no artefact.

The mental models — call stack, closure, the event loop, async behaviour — directly explain bugs developers hit daily. Experienced developers report the course clarified concepts they had used for years without fully understanding.

Covers responsive layout across two parts — Flexbox (grid systems, navigation, responsive images) and CSS Grid (Mondrian and magazine layouts, cards). Reviewers say it teaches modern layout "without hacks", though v2 predates subgrid and container queries.

Jen Kramer is the most-praised element — a long-time CSS educator who explains layout clearly and at a beginner-friendly pace. Learners and a Hacker News commenter call her CSS courses "very good" and her teaching "well taught, in-depth".

Requires a $39/month (or $390/year) Frontend Masters subscription rather than a one-time purchase — strong value if you use the wider catalog, weaker if you only want this one course. The course is included in the standard subscription.

More hands-on than most CSS courses: each section ends in build exercises and a capstone, including a Mondrian painting and magazine layouts. The builds are small practice pieces rather than a full portfolio site, but they reinforce the concepts well.

Flexbox and Grid are the everyday tools for production layout, and learners report finishing real site layouts noticeably faster afterward. The main gap is currency — the newer features (subgrid, container queries) are covered in Kramer's v3, not this version.