Schema linting in GraphQL - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the main purpose of schema linting in GraphQL?

Schema linting helps developers by:

• A. Checking the schema for errors and style issues before deployment
• B. Automatically generating queries from the schema
• C. Running queries faster by optimizing the schema
• D. Encrypting the schema for security

A Checking the schema for errors and style issues before deployment

B Automatically generating queries from the schema

C Running queries faster by optimizing the schema

D Encrypting the schema for security

💡 Hint

Think about what 'linting' usually means in programming.

Schema linting is the process of checking the GraphQL schema for mistakes or style problems before it is used. It helps catch errors early.

❓ query_result

intermediate

What error will this GraphQL schema linting tool report?

Given this schema snippet:

type User { id: ID! name: String! age: Int }

The linting tool requires all fields to have descriptions. What is the linting error?

A Missing description for field 'age'

B Missing description for field 'name'

C Missing description for field 'id'

D No errors found

💡 Hint

Check which fields lack descriptions.

The linting tool expects every field to have a description. Since 'id' has no description, it reports that error first.

📝 Syntax

advanced

Which schema snippet will cause a linting syntax error?

Identify the schema snippet that will fail linting due to syntax issues:

A type Query { user(id: ID!): User type User { id: ID! name: String! }

B type Query { user(id: ID!): User } type User { id: ID! name: String! }

C type Query { user(id: ID!): User } type User { id: ID! name: String! age: Int }

D type Query { user(id: ID!): User } type User { id: ID! name: String! } enum Role { ADMIN USER }

💡 Hint

Look for missing braces or keywords.

Option A is missing a closing brace for the Query type, causing a syntax error during linting.

❓ optimization

advanced

How can schema linting improve GraphQL API performance?

Choose the best explanation for how schema linting can indirectly improve API performance:

A By automatically caching all queries defined in the schema

B By encrypting schema fields to speed up data retrieval

C By compressing the schema file size to reduce network load

D By detecting inefficient schema designs that cause slow queries

💡 Hint

Think about how errors or bad designs affect query speed.

Linting can find schema design issues like deeply nested fields or missing indexes that slow down queries, helping developers fix them.

🔧 Debug

expert

Why does this schema linting tool report a duplicate type error?

Given these schema definitions:

type Product { id: ID! name: String! } type Product { sku: String! price: Float! }

What is the cause of the linting error?

A The 'Product' type is missing a description

B The 'Product' type is defined twice with different fields

C The 'Product' type fields have conflicting types

D The schema is missing a Query type

💡 Hint

Check if type names are unique in the schema.

GraphQL schemas cannot have two types with the same name. Defining 'Product' twice causes a duplicate type error during linting.