TypeScript adds a type system on top of JavaScript, catching a whole category of bugs before your code ever runs. This module covers basic type annotations first, then the tools that make TypeScript genuinely useful: interfaces, generics, and type narrowing — finishing with how it fits into a React codebase.
Most production frontend codebases use TypeScript today, so this is worth taking seriously. Work through these lessons in order, then move on to Testing to start verifying your code actually works.
What TypeScript catches that plain JavaScript can't, and how it fits into your build.
Annotating variables, function parameters, and return values with TypeScript's built-in types.
Describing the shape of objects, and when to reach for an interface versus a type alias.
Typing functions properly, and how much TypeScript can figure out on its own.
Combining types with unions, and narrowing them down safely inside conditionals.
Writing reusable, type-safe functions and components that work across different data types.
Built-in helpers like Partial, Pick, and Omit for transforming existing types.
Typing props, state, and event handlers in a real React component.
A written reference covering common types and patterns — good for a quick lookup after watching the videos.
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