Express JS Express REST API Development 2

Question 1

What is API versioning in Express and why is it important?

Accepted Answer

Prefixing routes with /v1, /v2 to support multiple API versions simultaneously

Answer

API versioning allows backward-compatible changes by maintaining multiple route prefixes so old clients aren't broken.

Question 2

How do you validate request body data in an Express REST API?

Accepted Answer

Use validation middleware like express-validator or joi before the route handler

Answer

Middleware libraries like express-validator or joi validate and sanitize incoming data before it reaches business logic.

Question 3

What is the purpose of pagination in a REST API endpoint that returns a list of resources?

Accepted Answer

To limit the number of items returned per request and reduce payload size

Answer

Pagination divides large datasets into manageable pages, improving performance and reducing data transfer.

Question 4

Which Express pattern is used to build a CRUD API for a 'users' resource with standard REST routes?

Accepted Answer

GET /users, POST /users, GET /users/:id, PUT /users/:id, DELETE /users/:id

Answer

RESTful conventions use noun-based plural paths with HTTP methods to express CRUD operations.

Question 5

What does HATEOAS stand for and how does it relate to Express REST APIs?

Accepted Answer

Hypermedia As The Engine Of Application State — including links in responses to guide clients

Answer

HATEOAS is a REST constraint where responses include links that describe available next actions, making APIs self-discoverable.

Express JS Practice Test