Inline fragments in GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an inline fragment in GraphQL?

An inline fragment lets you conditionally include fields in a query based on the type of the object. It helps when querying interfaces or unions to get fields specific to a certain type.

beginner

How do you write an inline fragment in a GraphQL query?

Use three dots followed by on TypeName inside curly braces. For example:<br>

{ ... on User { name } }

This fetches the name field only if the object is of type User.

intermediate

Why use inline fragments instead of separate queries?

Inline fragments let you get different fields for different types in a single query. This saves time and network calls, like ordering different toppings on one pizza instead of ordering many pizzas separately.

intermediate

Can inline fragments be used with interfaces and unions?

Yes! Inline fragments are especially useful with interfaces and unions because these types can represent multiple object types. Inline fragments let you ask for fields specific to each possible type.

beginner

What happens if the inline fragment type does not match the object type?

If the object type does not match the inline fragment type, the fields inside that fragment are ignored and not included in the result. This keeps the query safe and only returns relevant data.

What symbol starts an inline fragment in GraphQL?

A ::

B ...

C --

D ##

Inline fragments start with three dots (...) followed by 'on TypeName'.

Inline fragments are most useful when querying which GraphQL types?

A Input types

B Scalars

C Enums

D Interfaces and Unions

Interfaces and unions can represent multiple types, so inline fragments help fetch fields specific to each type.

If an inline fragment's type does not match the object, what happens?

A The fields inside the fragment are ignored

B All fields are returned anyway

C The query fails

D The server returns an error

Fields inside a non-matching inline fragment are ignored, so only relevant data is returned.

Which of these is a correct inline fragment syntax?

A ... on User { name }

B ... User { name }

C on User ... { name }

D fragment User on { name }

The correct syntax is three dots, 'on', then the type name, followed by the fields in braces.

Why use inline fragments instead of separate queries?

A To avoid using variables

B Because separate queries are not allowed

C To reduce network calls and get different fields in one query

D To make queries longer

Inline fragments let you fetch fields for different types in one query, saving time and network resources.

Explain what inline fragments are and why they are useful in GraphQL queries.

Think about how you get different info for different types in one request.

Write the syntax for an inline fragment that fetches the 'title' field only if the object is of type 'Book'.

Use ... on TypeName { fields } format.