Deep JavaScript Foundations, v3 vs Complete Intro to React v9

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.

v9 covers React 18 and 19 features (form actions, Suspense, the React Compiler) plus a modern Vite + TanStack Router + TanStack Query stack. Praised for currency, with a minority of long-term Frontend Masters subscribers flagging that other courses in the catalog can drift.

Brian Holt is the most consistently praised aspect across nine years of Hacker News mentions. Learners use words like 'excellent', 'great', and 'brilliant'. His pet adoption project framing is repeatedly cited as memorable.

Requires a Frontend Masters subscription (currently $39/month), which is consistently described as worth it if you complete more than one course per month. Less competitive against free alternatives if you only want a single React intro.

The single build-along project (an e-commerce app in v9, evolved from the pet adoption app of earlier versions) is praised for being non-trivial and integrating real ecosystem tools (TanStack Query, Vitest) rather than toy examples.

Holt spends real time on tooling (Vite, ESLint, Prettier, code-splitting, Vitest) and modern ecosystem choices, which is the single most-cited reason people say his courses transferred well to their day jobs.