req.query for query strings in Express - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is req.query in Express?

req.query is an object in Express that holds the query string parameters sent in the URL of a GET request.

beginner

How do you access a query parameter named name in Express?

You use req.query.name to get the value of the name parameter from the URL query string.

beginner

Example URL: /search?term=books&sort=asc. How does req.query look?

req.query will be an object: { term: 'books', sort: 'asc' }.

beginner

What type of data does req.query contain?

req.query contains all query parameters as strings inside an object. Even numbers or booleans come as strings.

intermediate

Can req.query handle multiple values for the same key?

Yes, if the URL has repeated keys like ?tag=js&tag=node, req.query.tag will be an array: ['js', 'node'].

What does req.query represent in Express?

A An object containing URL query parameters

B The body of a POST request

C The headers of the HTTP request

D The cookies sent by the client

req.query holds the query string parameters from the URL, like ?key=value.

How do you access the value of ?page=3 in Express?

A <code>req.headers.page</code>

B <code>req.query.page</code>

C <code>req.body.page</code>

D <code>req.params.page</code>

Query parameters are accessed via req.query.

If the URL is /items?color=red&color=blue, what is req.query.color?

A 'red'

B undefined

C 'blue'

D ['red', 'blue']

Repeated query keys become arrays in req.query.

What data type are values inside req.query?

A Strings

B Numbers

C Booleans

D Objects

All query values come as strings by default.

Which HTTP method usually sends data accessible via req.query?

A PUT

B POST

C GET

D DELETE

Query strings are mostly used with GET requests.

Explain how req.query works in Express and how you use it to get query string values.

Think about how URLs have ?key=value and how Express reads that.

Describe a real-life example where you might use req.query in a web app.

Imagine a shopping site where you filter products by category or price.