Sorting with sort parameter in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this REST API call with sort parameter?

Consider an API endpoint that returns a list of users sorted by age ascending when called with ?sort=age. What will be the order of user IDs in the response?

Rest API

GET /users?sort=age

Response JSON:
[
  {"id": 3, "name": "Alice", "age": 22},
  {"id": 1, "name": "Bob", "age": 25},
  {"id": 2, "name": "Charlie", "age": 30}
]

A [3, 1, 2]

B [1, 2, 3]

C [2, 1, 3]

D [3, 2, 1]

💡 Hint

Sorting by age ascending means the youngest user comes first.

The API sorts users by their age in ascending order, so the user with age 22 (id 3) comes first, then age 25 (id 1), then age 30 (id 2).

🧠 Conceptual

intermediate

Which sort parameter value sorts results by name descending?

You want to get a list of products sorted by their name in reverse alphabetical order using a REST API. Which sort parameter value should you use?

A sort=name_desc

B sort=-name

C sort=name_reverse

D sort=desc_name

💡 Hint

Many APIs use a minus sign before the field name to indicate descending order.

The common convention is to prefix the field with a minus sign to sort descending, so sort=-name sorts by name descending.

🔧 Debug

advanced

Why does this API call with sort parameter cause an error?

An API call GET /items?sort=price,desc returns a 400 Bad Request error. What is the likely cause?

A The API expects a single field without comma, not 'price,desc'.

B The sort parameter should be 'sort=price-desc' instead of comma.

C The API requires 'sort=desc:price' format.

D The API does not support sorting by price.

💡 Hint

Check the API documentation for the expected format of the sort parameter.

The API expects the sort parameter to be a single field name optionally prefixed by a minus sign for descending order. Using a comma is invalid syntax.

❓ Predict Output

advanced

What is the output order of this API call with multiple sort fields?

An API supports sorting by multiple fields separated by commas. Given the call GET /books?sort=author,title, what is the order of books?

Rest API

Books data:
[
  {"author": "Smith", "title": "Zebra"},
  {"author": "Smith", "title": "Apple"},
  {"author": "Adams", "title": "Banana"}
]

Sorted by author ascending, then title ascending.

A [{"author": "Smith", "title": "Zebra"}, {"author": "Smith", "title": "Apple"}, {"author": "Adams", "title": "Banana"}]

B [{"author": "Smith", "title": "Apple"}, {"author": "Smith", "title": "Zebra"}, {"author": "Adams", "title": "Banana"}]

C [{"author": "Adams", "title": "Banana"}, {"author": "Smith", "title": "Apple"}, {"author": "Smith", "title": "Zebra"}]

D [{"author": "Adams", "title": "Banana"}, {"author": "Smith", "title": "Zebra"}, {"author": "Smith", "title": "Apple"}]

💡 Hint

Sorting by multiple fields means sorting by the first field, then by the second field within ties.

The books are sorted first by author ascending: Adams before Smith. For books with the same author (Smith), they are sorted by title ascending: Apple before Zebra.

🚀 Application

expert

How to implement sorting with a sort parameter in a REST API?

You are building a REST API that returns a list of products. You want to add a sort query parameter that supports sorting by one or more fields, each optionally descending with a minus sign prefix. Which approach correctly implements this?

A Only allow sorting by one field without descending option, reject requests with multiple fields or minus sign.

B Ignore the sort parameter and always return products sorted by ID ascending.

C Sort products randomly regardless of the sort parameter to improve performance.

D Parse the sort parameter by splitting on commas, then for each field check if it starts with '-', sort descending by that field, else ascending.

💡 Hint

Think about how to handle multiple fields and descending order indicated by a minus sign.

The best approach is to parse the sort parameter by commas, detect descending order by a minus sign prefix, and apply sorting accordingly for each field in order.