TypeScript at work
A course about how types catch mistakes before you run the code — not about type theory. We take the shop from «React in practice» and move it to TypeScript file by file: props, state, server data, custom hooks. By the end you can read someone else's typed project without dread.
What you will be able to do
8 modules, one project
01 Why types2 lessons · 1 h 24 minOpen
What types really catch, what they do not, and why a project is migrated in pieces rather than in one evening.
02 The types of your application data2 lessons · 1 h 32 min
We describe the product, the user and the order — the same entities the shop already has.
03 Functions, narrowing and unions3 lessons · 2 h 14 min
The main working technique of TypeScript: a check in the code after which the type becomes exact.
04 Props and children2 lessons · 1 h 34 min
Components with a typed interface: what is required, what is not and how to describe children and ref.
05 State and events3 lessons · 2 h 18 min
useState, forms and handlers: the place where a beginner most often writes any and loses the whole benefit.
06 Generics without fear2 lessons · 1 h 36 min
Generics on your own hooks: concrete code first, generalisation second — and then the point of them becomes clear.
07 Server data2 lessons · 1 h 32 min
A type does not guarantee that the server sent exactly that: we validate the data at the boundary of the application.
08 Migrating the whole project2 lessons · 1 h 50 min
The final module: we turn strictness on step by step and remove the last any from the shop.
What you get
Videos with timecodes and a written version: the code from a lesson is copied together with the compiler messages.
The same project in JavaScript in its starting state and its typed version — you can compare them file by file.
Twenty typical messages translated into human language, with an explanation of what exactly to fix.
A tsconfig for strict and for lenient mode, with a comment on every flag — so you can turn strictness on gradually.
The whole first module is open
Watch the lessons of the first module and the first task. If the format does not suit you, you have lost nothing.