Every Udemy Course is Free
Right now you don't need to pay ANYTHING for any online course.
I was thinking about buying some courses about backend development and then I realized:
The biggest blocker is no longer the information you have access to. No, the internet has literally everything, especially for web development which is largely open source and documented.
The only blocker is knowing WHAT to learn -and so peoples' courses with tables of contents tell us all of the intricacies of what we don't know to search for yet!
The first 60% of a udemy course will be discovered by any beginner. Another 20% will come from a year or so of experience. But the final 20% is for the truly seasoned. Those are advanced concepts that a beginner doesn't know because they simply don't know what to search for.
That's the real value from these courses -you can essentially just extract these learning "success criteria" and find it yourself on YouTube, documentation, and the like.
It's as easy as pasting a set of Udemy Table of Contents into ChatGPT and asking for that last 20%.
This is the set of topics to learn from a React.js Udemy table of contents :
10 React Concepts That Separate Juniors from Pros
There’s a big leap between building to-do apps and architecting robust, production-grade UIs. Here are 10 under-the-radar concepts every React developer should eventually master — plus a few bonus ideas that professionals obsess over.
1. React Server Components (RSC)
Introduced in React 18 and evolving in React 19, Server Components challenge the traditional client-heavy rendering model. They allow developers to move logic to the server without duplicating code, offering zero bundle size on the client for server-only concerns. Most juniors don’t even know this exists, yet it’s foundational for building fast, scalable apps.
2. useImperativeHandle
Ever needed to trigger a child component’s method from the parent? That’s where useImperativeHandle comes in. While rarely needed, it’s essential when building reusable component libraries or complex UIs like modals, carousels, or design systems.
3. Portals
Portals let you render elements outside the main DOM tree — vital for modals, tooltips, and dropdowns. They’re not just a neat trick; they’re crucial for maintaining accessibility, focus control, and layout integrity.
4. useReducer with Context
When your app’s state becomes hard to track, useReducer combined with Context offers a scalable solution. It mimics Redux’s predictability without the boilerplate, making it perfect for medium to large apps that outgrow useState.
5. Performance Optimizations
Hooks like React.memo, useMemo, and useCallback can help — but they aren’t magic bullets. They’re tradeoffs, and misusing them can harm performance. Knowing when not to use them is what sets pros apart.
6. Custom Hooks as Abstractions
Custom hooks aren’t just syntactic sugar — they help you build clean, reusable logic layers. Whether it’s handling forms, fetching data, or managing modals, mastering custom hooks means you’re no longer just writing components — you’re designing infrastructure.
7. Form Actions (React 19+)
The new Form Actions API brings progressive enhancement to the forefront. Even if JavaScript fails, the server handles submissions. This marks a shift from JavaScript-first thinking to graceful, resilient design.
8. TanStack Query (React Query)
React Query abstracts away much of the boilerplate around fetching, caching, and synchronizing server data. It’s a must-have in data-heavy apps and can even eliminate the need for Redux entirely in many cases.
9. Auth + Routing + Data Fetching
Combining authentication, route protection, and server/client data-fetching flows (especially in frameworks like Next.js) is complex. Many juniors copy boilerplate without truly understanding how auth, middleware, and redirects should interact.
10. Next.js App Router Mental Model
The new App Router in Next.js introduces nested layouts, server components, and the use client directive. Understanding how to isolate interactivity while optimizing hydration and caching is key to building fast, maintainable Next apps.
Bonus: Meta Concepts Pros Think About Constantly
- Unidirectional data flow, even with shared or global state.
Colocating and normalizing state to avoid prop drilling and tight coupling.
Designing ergonomic component APIs (props, accessibility, function signatures).
Deciding when to fetch data statically vs at runtime — preload, defer, cache, mutate?
Building design systems with Tailwind, Styled Components, or CSS-in-JS.
The Real Barrier?
Sure, maybe the course content is "all in one place" and the explainer might explain better than youtube videos and google searches we find. But the fact is, if we're dedicated, we can learn all of the same content ourselves.
The barrier isn't the amount of courses we can pay for. It's the amount of focused time we put into learning.