TypeScript for JavaScript Developers
Types that catch real bugs, without turning your codebase into a puzzle
Created by Amara Osei
What you will learn
- Model your data with unions, literals and discriminated unions
- Read the error messages the compiler actually gives you
- Use generics where they earn their keep and avoid them where they do not
- Type third-party libraries and untyped JSON safely
- Migrate an existing JavaScript codebase incrementally
- Configure tsconfig without cargo-culting someone else's
Course content
13 sections · 96 lectures · 14h 30m total length
- What this course covers, and what it does notPreview04:00
- How to get the most out of itPreview04:00
- Setting up and downloading the exercise files06:00
- The type system's shapePreview15:00
- The type system's shape in detail07:00
- A closer look at the type system's shape06:00
- Worked example: the type system's shape11:00
- Where the type system's shape goes wrong10:00
- Exercise: the type system's shape14:00
- The type system's shape in practice13:00
- Two approaches to the type system's shape05:00
- The type system's shape — questions from previous students04:00
Topics covered
Requirements
- Solid JavaScript — this course assumes the language, not the types
- A project you would like to add types to helps, but is not required
Description
TypeScript is easy to adopt badly — `any` everywhere, or type gymnastics nobody on the team can read. This course sits in the useful middle: enough of the type system to model your domain properly, and clear guidance on when to stop.
Your instructor
Staff engineer, teaching JavaScript since 2014
Amara has spent eleven years building large front-end codebases and the last six teaching people how to work in them. Her courses avoid clever tricks in favour of the boring patterns that survive a team of thirty and a two-year rewrite.
Learner reviews
- 5 star73%
- 4 star22%
- 3 star3%
- 2 star1%
- 1 star1%
- JDJonas D.6 February 2026
Very practical. I applied something from module four at work the same week.
- FGFarid G.2 October 2025
Exactly what I needed. It assumes you are an adult and does not over-explain.
- NLNiall L.7 January 2026
Clear explanations without the usual filler. I watched most of it at 1.25x and still followed everything.
- WOWei O.5 March 2026
Worth it for the section on common mistakes alone — I recognised two things I have been doing wrong for years.
- SDSam D.5 October 2025
The pacing is right. Nothing is padded out, and the exercises are short enough that I actually did them.
- SRSam R.11 February 2026
I came in knowing a bit and still learned plenty. The middle third is the strongest part.
- ZLZoe L.1 April 2026
Good balance between theory and doing. I would have liked a couple more exercises, but that is a small complaint.
- ZKZoe K.3 December 2025
Worth it for the section on common mistakes alone — I recognised two things I have been doing wrong for years.
- KSKemi S.2 March 2026
Very practical. I applied something from module four at work the same week.
Showing 9 of 4,021 reviews.
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