TypeScript Risk Assessment & Management 4

Question 1

A developer writes an async function that can throw, but callers never await it. Which TypeScript configuration helps surface this risk?

Accepted Answer

Enabling the ESLint @typescript-eslint/no-floating-promises rule alongside strict mode

Answer

TypeScript alone does not flag unawaited promises; the no-floating-promises ESLint rule catches cases where a Promise is silently discarded.

Question 2

Which type guard pattern provides the safest runtime risk mitigation when consuming data from an external API?

Accepted Answer

A user-defined type guard with runtime validation (e.g., using zod or manual checks)

Answer

Runtime validation libraries like zod verify that external data actually matches the expected shape, catching schema mismatches before they propagate through the app.

Question 3

What is the risk of declaring a variable with 'let' but never reassigning it in a TypeScript project?

Accepted Answer

It signals intent incorrectly; using 'const' makes mutability guarantees clear and reduces accidental reassignment bugs

Answer

Using const for values that never change communicates immutable intent and allows TypeScript and engines to optimize, while let implies (misleading) mutability.

Question 4

A library exported interface is extended by consumers via module augmentation. What versioning risk does this introduce for the library author?

Accepted Answer

Adding a required property to the interface in a minor version is a breaking change for consumers who augmented it

Answer

If a library adds a required property to an interface that consumers have augmented, those consumers must add the property too, making the change breaking despite a minor version bump.

Question 5

Which approach best mitigates the risk of type drift between a TypeScript frontend and a backend API over time?

Accepted Answer

Generating shared TypeScript types from a single source of truth such as an OpenAPI spec or Protobuf schema

Answer

Code generation from a shared contract ensures both sides always agree on types, eliminating drift caused by independent manual updates.

TypeScript Practice Test

TypeScript Practice Test

TypeScript Risk Assessment & Management 4