TL;DR: Know JavaScript first, then learn inference, unions, objects, functions, narrowing, generics, utility types, modules, and typed API boundaries. Practice by converting a real project instead of memorizing every advanced type.
Learn These Concepts in Order
Start with primitive types, arrays, objects, function parameters, return types, unions, and literal types. Continue with narrowing, discriminated unions, generics, utility types, modules, declaration files, and strict compiler settings.
The Best First Project
Convert a small JavaScript task manager to strict TypeScript. Type the domain model, form input, API response, error state, and reusable components. Let compiler errors guide the next lesson.
Avoid the Common Trap
Do not use any to make errors disappear. When the data is unknown, validate it at the boundary and narrow it inside the application. Types describe assumptions; runtime validation checks reality.
TypeScript with React
Learn component props, event types, children, refs, forms, and async state. Type the data model first, then make components consume that model so the compiler can protect changes across the UI.
Practice Checkpoint
You are ready to move on when you can model a feature without any, explain a union versus an intersection, write a generic helper, and safely consume an untrusted JSON response.