TypeScript Project Planning & Execution 2

Question 1

Which `tsconfig.json` option enforces that all switch statement cases are exhaustively handled using never-type checks?

Accepted Answer

noFallthroughCasesInSwitch

Answer

`noFallthroughCasesInSwitch` causes a compiler error when a switch case falls through to the next without a break or return.

Question 2

When migrating a large JavaScript project to TypeScript incrementally, which file extension should you use to allow importing JS files without type errors?

Accepted Answer

allowJs: true in tsconfig

Answer

Setting `allowJs: true` in tsconfig.json lets TypeScript include and type-check JavaScript files alongside TypeScript files during migration.

Question 3

Your team wants TypeScript to emit no JavaScript output but still type-check the project. Which tsconfig option achieves this?

Accepted Answer

noEmit: true

Answer

`noEmit: true` instructs TypeScript to perform type checking without writing any output files.

Question 4

Which monorepo tool uses TypeScript project references (`composite: true`) to enable incremental builds across packages?

Accepted Answer

tsc --build mode

Answer

`tsc --build` (or `tsc -b`) mode reads project references in tsconfig and builds only changed packages incrementally.

Question 5

A CI pipeline should fail when new TypeScript errors are introduced. Which command exits with a non-zero code on type errors without emitting files?

Accepted Answer

tsc --noEmit

Answer

`tsc --noEmit` type-checks the project and returns a non-zero exit code if errors exist, making it ideal for CI gates.

TypeScript Practice Test

TypeScript Practice Test

TypeScript Project Planning & Execution 2