tech-studies

TypeScript

2 min read

TypeScript

roadmap.sh: https://roadmap.sh/typescript

Suggested path through the TypeScript nodes. Each node links to its lesson when written.

Nodes

Introduction

  • What is TypeScript
  • TypeScript vs JavaScript
  • TS / JS interoperability
  • Installing TypeScript (tsc, ts-node)

TypeScript Setup

  • tsconfig.json
  • Compiler options & strict mode
  • Running the TypeScript compiler

TypeScript Types

  • Primitive types (string, number, boolean)
  • Object types
  • Arrays
  • Tuples
  • Enums
  • any
  • unknown
  • never
  • void
  • null & undefined

Type Inference

  • Inference basics
  • Contextual typing
  • const assertions

Type Compatibility

  • Structural typing
  • Type widening & narrowing

Combining Types

  • Union types
  • Intersection types
  • Type aliases
  • Type guards / narrowing
  • keyof operator
  • typeof operator
  • Indexed access types
  • Conditional types
  • Literal types
  • Template literal types

Functions

  • Typing function parameters & return values
  • Optional & default parameters
  • Rest parameters
  • Function overloads
  • this parameter

Interfaces

  • Defining interfaces
  • Extending interfaces
  • Interfaces vs type aliases
  • Index signatures

Classes

  • Class members & constructors
  • Access modifiers (public, private, protected)
  • readonly
  • Inheritance & implements
  • Abstract classes
  • Parameter properties
  • Getters & setters

Generics

  • Generic functions
  • Generic classes & interfaces
  • Generic constraints
  • Default type parameters

Decorators

  • Class decorators
  • Method & property decorators
  • Decorator metadata

Utility Types

  • Partial & Required
  • Readonly
  • Pick & Omit
  • Record
  • Exclude & Extract
  • ReturnType & Parameters
  • Awaited
  • NonNullable

Advanced Types

  • Mapped types
  • Recursive types
  • Discriminated unions
  • satisfies operator

Modules

  • ES Modules
  • Namespaces
  • Module resolution
  • Declaration files (.d.ts)
  • DefinitelyTyped (@types)

Ecosystem & Tooling

  • ESLint with TypeScript
  • Prettier
  • Type-aware bundlers (tsup, esbuild, swc)
  • Migrating a JS project to TS

Resources

See resources.md.

Project ideas

  • Convert an existing small JavaScript library to strict-mode TypeScript and publish typings.
  • Build a fully-typed REST API client using generics and discriminated unions for responses.
  • Implement a type-safe form validation utility using mapped and conditional types.

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