TypeScript Project Planning & Execution 4

Question 1

Your TypeScript library is published to npm. Which tsconfig option generates `.d.ts` files so consumers get type information?

Accepted Answer

declaration: true

Answer

`declaration: true` instructs TypeScript to emit `.d.ts` files alongside compiled JavaScript, providing type info to library consumers.

Question 2

Which versioning strategy should a TypeScript project library follow when making breaking changes to exported types?

Accepted Answer

Major version bump (1.0.0 → 2.0.0)

Answer

Breaking changes to exported types are breaking API changes and require a major semver bump to signal incompatibility.

Question 3

In a TypeScript project, what is the role of `husky` and `lint-staged` in the development workflow?

Accepted Answer

They run linting and type checks only on staged files before each commit

Answer

`husky` sets up Git hooks and `lint-staged` runs scripts (lint, format, type check) only on staged files to keep commits clean.

Question 4

When planning a TypeScript migration from JavaScript, which flag helps you gradually add types by only erroring on explicitly typed code?

Accepted Answer

allowJs: true with noImplicitAny: false

Answer

Using `allowJs: true` with `noImplicitAny: false` lets JS files coexist with TypeScript without requiring all types immediately.

Question 5

Which TypeScript compiler option must be enabled to use experimental decorators (e.g., for frameworks like NestJS)?

Accepted Answer

experimentalDecorators

Answer

`experimentalDecorators: true` enables the Stage 2 decorator proposal syntax used by frameworks like NestJS and Angular.

TypeScript Practice Test