lrnit
For React developers

Learn TypeScript in a course built only for you. And actually retain it.

Go beyond any: generics, discriminated unions, and the type patterns that make React components self-documenting and refactors fearless.

Free to start · no account needed
Built around your goal, not a catalog

What your course could open with

lrnit interviews you first (what you know, why you’re learning, how you think), then generates every lesson for that. Sample lessons from a course like yours:

  1. 01Props as contracts: typing components so misuse won’t compile
  2. 02Discriminated unions: modeling UI states that can’t be wrong
  3. 03Generics in practice: a typed useFetch you’ll actually reuse
  4. 04The migration playbook: converting a JS codebase without stopping ship
  5. …and the rest is generated for you: your gaps, your pace, your job.
Measured, not watched

By the end, you’ll be able to

What a capability check looks likebeforenow
Type component props+59
Model UI states safely+61
Migrate JS incrementally+63

Every lesson ends in assessment. Mastery is tracked per concept with spaced review, and the course adapts to what you actually retain. Finishing means a timed final exam and a verifiable certificate, not a completion badge.

“It felt like the course already knew what I did for a living.”
Early lrnit learner

Questions people ask

How much React and TypeScript do I need first?
Solid React and some JavaScript. You do not need TypeScript beyond the basics; the course takes you past any into generics and discriminated unions.
Will it help me migrate an existing JS codebase?
Yes. There is a migration playbook for converting a JavaScript codebase incrementally without stopping ship.
Does it stay focused on component code?
Yes. The types it teaches are the ones that catch real bugs in props, state, and hooks, checked against real component scenarios.

Your version of this course doesn’t exist yet.

Free to start · no account needed
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