After this lesson, you will be able to: Explain why TypeScript exists, what it solves, and the tradeoffs.
TS won the 2020s. This sub-track teaches it from the JS dev's perspective.
This is a free introductory lesson. No purchase required.
Compile-time type checking, catches typos + wrong-type bugs before runtime. Better tooling, autocomplete, refactoring, find-references. Documentation that doesn't rot, types stay in sync with code. Easier onboarding, new devs read types instead of guessing.
Build step, `tsc` (or esbuild/swc) compiles to JS. Type system has gaps, `any`, casts, deps without types. Learning curve, generics + conditional types are non-trivial. Tradeoff: tax up front for fewer runtime bugs + better refactor confidence over years.
VS Code uses TS by default; React, Vue, Svelte, Next.js all ship native TS. Microsoft committed via tsc + VS Code; ecosystem followed. Node 22+ ships type-stripping (run .ts files directly). JSDoc + checkJs is a partial-adoption path for legacy JS codebases.
Pick the cleanest answer.