Deep JavaScript Foundations, v3 vs Modern React with Redux

Reviewers consistently describe the curriculum as the deepest treatment of core JavaScript available in video form. The three pillars — types and coercion, scope and closure, and the this/prototype object system — are explained directly from the language specification rather than from surface behaviour. Gurpreet Singh's testimonial captures the consensus: "I know of no other resource that goes this deep into fundamentals of JS." The main critique is that some sections, particularly the OLOO delegation pattern in the object-oriented module, are presented as settled best practice when many experienced developers disagree.

Kyle Simpson, author of the You Don't Know JS book series, is widely praised for clarity and depth. Lara Karki called him "not only brilliant, but an excellent and articulate teacher" and Hatem Hassan noted he "has a unique way of explaining deep technical CS concepts in a simple and straightforward manner." The score is held below the instructor scores of less polarising teachers because his opinionated, prescriptive style draws genuine criticism — one HN commenter found his persona "very off-putting" and others object to his advocacy for == coercion.

The course is bundled into the Frontend Masters subscription at $39/month or $390/year, which also unlocks the entire library including Kyle's scope, closures, and asynchronous JavaScript courses. Lara Karki called the membership "the best $40 I'll spend this month, by far." Value is excellent for committed learners but the subscription model means a single 10.5-hour course is not buyable standalone, which frustrates learners who only want this one title.

The course makes developers materially better at reading and reasoning about production JavaScript — Kevin O'Shaughnessy noted it "blew my mind how much there was going on in 10 lines of code." However, it is conceptual rather than project-based: there is no application built end to end, no framework, and no tooling. Reviewers who wanted to ship something tangible note that this is a foundations course, and its payoff shows up later as fewer bugs and clearer mental models rather than a portfolio piece.

Frontend Masters provides downloadable exercise files, transcripts, and a hosted course platform with adjustable playback speed, but there is no graded auto-grader, no mentor, and no certificate. Learners rely on the public GitHub note repositories and exercise mirrors that other students have published. This is a lecture-and-exercise format, not a guided cohort, so self-directed learners do best.

The standout is Grider's diagram-driven explanation. Reviewers repeatedly praise how he explains everything "bit by bit" with custom mockups and visuals, and deliberately walks through common mistakes before the preferred fix. The catch: at 75+ hours some sections cover older class-component and legacy Redux material learners no longer need.

Grider is one of the most consistently praised instructors on Udemy. Across blogs and Hacker News, developers call his courses "outstanding" and say his style is exceptionally clear. The 4.7 Udemy rating across ~89,000 ratings reflects this. The only recurring note is that his slow, thorough pace does not suit everyone.

On Udemy's frequent sales (~$15), 75+ hours of well-structured, frequently updated content is a strong deal, and reviewers say it is "worth every penny." It still loses a little because part of that runtime is legacy material, so the effective value is high but not every hour is essential.

The course is hands-on and project-based, which most learners value. But the most common criticism is that it lacks real challenges — the projects are largely follow-along, with no exercises where the student must implement features alone. Some also flag unexplained Bootstrap styling that complicated their own later builds.

It covers modern, employable React — hooks, Context, React Router, TypeScript, and Redux Toolkit in recent updates — and developers report it genuinely prepared them. The honest gap is depth on testing and the lingering legacy Redux sections, which can leave beginners unsure which patterns are current.