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TS Summary
If you've worked through every lesson, here's what you can now do — and where to go next.
You can
- Read and write modern TypeScript with confidence — types, generics, classes, interfaces.
- Model real-world data with unions, intersections, discriminated unions, literal types.
- Use the advanced type system —
keyof,typeof, mapped types, conditional types, template literals. - Apply utility types to shape data transformations.
- Configure a project —
tsconfig.json, strict mode, path aliases, library targets. - Lint with ESLint, format with Prettier, test with Vitest, build with esbuild / Vite / tsc.
- Run TS scripts with
tsxand set up monorepo project references.
Where to go next
| Direction | Why |
|---|---|
| A framework | React, Vue, Svelte, Solid, Hono, Nest, Next — all TS-first. |
| Schema validation | Zod, Valibot, ArkType — type-safe runtime validation. |
| End-to-end type safety | tRPC, GraphQL Code Generator, Hono RPC. |
| Advanced type theory | Recursive conditional types, distributive analysis, branded types. |
| State management | Discriminated unions for state machines — XState, Zustand. |
| Documentation | TypeDoc, Mintlify, fumadocs — generate docs from your types. |
One last habit
Before exporting a function from a module, ask three questions:
- Is every parameter typed as narrowly as possible?
- Is the return type annotated (or obviously inferred)?
- Could a discriminated union replace a "many optional fields" object?
Tip: TypeScript is a tool for shipping fewer runtime errors. When in doubt, lean on the compiler. If something is hard to type, the runtime behaviour is probably hard too — that's a signal to redesign.
Example
Example
// You can now: write typed functions, model data with unions / generics,
// configure tsconfig, lint, format, test, and ship.
// Next: a framework (React, Vue, Svelte, Hono, NestJS), advanced generics.
console.log('Time to build something real.');
Try it Yourself »
Exercise
Popular schema-validation library to learn next.
Three letters.
Test yourself
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