JavaScript: The Hard Parts, v2 vs Learn React

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.

11 lessons cover JSX, components, props, state, Hooks and React programming patterns. Rebuilt around function components and Hooks in the 2020 refresh. Solid intermediate scope, but stops short of routing, data fetching and state libraries.

No single named instructor — the course is platform-authored with written steps, animations and an AI helper rather than video lectures. Clear and consistent, but lacks the narrative voice some learners prefer for a hard topic like React.

The course sits behind Codecademy Pro (~$30/month) for projects, quizzes and the certificate. Fair for the interactive practice, but free alternatives like Scrimba's and freeCodeCamp's React content cover similar ground.

Seven guided projects apply JSX, Hooks and forms inside the browser sandbox. Good for reinforcement, but they hold your hand and run in a simplified environment — you do not configure tooling or deploy anything real.

Teaches genuinely current React (Hooks, function components) that transfers to real codebases. The gap is the jump from sandbox exercises to a real editor, build tooling and a deployed app — learners must bridge that themselves.