TypeScript Technology & Digital Tools 4

Question 1

Which Jest configuration is needed to run TypeScript tests without a separate compile step?

Accepted Answer

ts-jest or babel-jest with @babel/preset-typescript

Answer

`ts-jest` or `babel-jest` with the TypeScript preset transforms `.ts` files on-the-fly so Jest can execute them.

Question 2

What does the `moduleResolution` option `bundler` (added in TypeScript 5.0) enable?

Accepted Answer

Resolution logic matching modern bundlers like Vite and esbuild, supporting package.json exports

Answer

`moduleResolution: bundler` aligns TypeScript's import resolution with tools like Vite and webpack that use `package.json` `exports` fields.

Question 3

Which tool can automatically add missing `@types/*` packages to a project based on imported modules?

Accepted Answer

typesync

Answer

`typesync` scans your `package.json` dependencies and installs any missing `@types/*` packages from DefinitelyTyped.

Question 4

What is the advantage of using `esbuild` over `tsc` for production builds in large TypeScript projects?

Accepted Answer

esbuild transpiles TypeScript significantly faster by stripping types without type checking

Answer

esbuild is written in Go and strips TypeScript types without running the type checker, making builds 10-100× faster than `tsc`.

Question 5

What does the `composite` option in `tsconfig.json` enable?

Accepted Answer

Enables project references and incremental builds across multiple TypeScript subprojects

Answer

`composite: true` is required for TypeScript project references, enabling incremental builds that only recompile changed subprojects.

TypeScript Practice Test