This program teaches TypeScript 7 to developers who know a little JavaScript and no TypeScript. Every example is typed on screen, checked by the compiler and run in Node, with TypeScript pinned at exactly 7.0.2, so what you see is what you install.

You start from an empty folder: install Node.js and npm, compile your first file, and learn to read compiler errors, strict mode and tsconfig.json. Next come the types you meet in real code: arrays, tuples, objects, unions and narrowing, null and unknown. Then you write reusable code with typed functions, generics, classes and ES modules. With the language in hand, you set up a professional toolchain with Node's test runner, Vitest, type tests, Oxlint, Prettier, npm scripts and CI, and learn to trust data from outside your program by validating JSON, files, HTTP responses and environment variables with Zod.

Each course builds a small project of its own: a unit converter, a typed shopping cart, a typed library, a reusable project template and a validated data loader. Taken in order, the courses take you from your first type error to a command-line tool you build, test, package and install with npm.

Applied Learning Project

In the capstone you build a todo command-line tool in TypeScript 7, starting from a starter repository, and a contract check decides when it is done. It parses options and positional arguments with Node's argument parser, adds, completes and lists todos, sends errors to standard error and returns exit codes that scripts can rely on. It loads and saves its todo file, validates it with Zod, and prints plain text or JSON. You cover it with unit tests on Node's test runner, tests that spawn the CLI, coverage, type tests, type-aware linting with Oxlint and formatting checks with Prettier, all behind one npm script. Then you build it with tsdown and type declarations, pack it with npm, install the tarball in a clean folder, run the installed command, and rehearse a publish.