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TypeScript Deep Dive

Go past the annotations. Learn how the type system actually reasons, write generics that stay readable, and take a large JavaScript codebase to strict mode.

Intermediate2h 29m4 modules24.7k students

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What you'll learn

Reason like the compiler

Predict how a type is inferred and narrowed instead of adding annotations until the error goes away.

Write generics people can read

Use constraints, defaults, and conditional types to build APIs that infer well at the call site.

Type the edges safely

Validate data arriving from APIs and forms at runtime so your types describe reality.

Migrate a real codebase

Move an existing project to strict mode incrementally, without freezing feature work.

Course Content

4 modules • 2h 29m

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Start Learning

TypeScript Deep Dive

What you'll learn

Reason like the compiler

Write generics people can read

Type the edges safely

Migrate a real codebase

Course Content

1The Type System UnderneathHow TypeScript decides two types are compatible, and how it narrows a value as your code branches.29m

2Generics That Earn Their KeepBuilding reusable types that infer well, without turning your codebase into a puzzle.39m

3Typing Real CodebasesThe problems that only appear once the project is large, shared, and already running in production.54m

4Tooling and BuildCompiler configuration, project layout, and closing the gap between compile time and runtime.28m