Schema linting in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a GraphQL type with a non-nullable String field called 'name'.

GraphQL

type User { name: [1] }

Drag options to blanks, or click blank then click option'

AFloat

BInt

CBoolean

DString!

Attempts:

3 left

💡 Hint

Common Mistakes

Using just 'String' without the exclamation mark.

Using a wrong type like 'Int' or 'Boolean' for a name field.

The exclamation mark ! after String means the field is non-nullable, which is required here.

2fill in blank

medium

Complete the code to add a description to the 'User' type using GraphQL schema comments.

GraphQL

"""[1]"""
type User { id: ID! }

Drag options to blanks, or click blank then click option'

AList of users

BUser ID field

CUser represents a system user

DQuery for users

Attempts:

3 left

💡 Hint

Common Mistakes

Putting a field name instead of a description.

Using single quotes instead of triple quotes.

Triple quotes """""" are used to add descriptions in GraphQL schemas. The description should explain the type.

3fill in blank

hard

Fix the error in the schema by completing the code to define a list of non-nullable 'Post' types inside 'User'.

GraphQL

type User { posts: [[1]]! }

Drag options to blanks, or click blank then click option'

APost

BPost!

CPost[]

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Post' without exclamation mark inside the list.

Using invalid syntax like 'Post[]'.

The Post! inside the list means each post cannot be null. The list itself is non-nullable because of the exclamation mark after the brackets.

4fill in blank

hard

Fill both blanks to define a mutation 'createUser' that takes a non-nullable 'name' argument of type String and returns a 'User'.

GraphQL

type Mutation { createUser(name: [1]): [2] }

Drag options to blanks, or click blank then click option'

AString!

BUser

CBoolean

DInt

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the exclamation mark on the argument type.

Returning a wrong type like Boolean or Int.

The argument 'name' must be a non-nullable String, so use String!. The mutation returns a User type.

5fill in blank

hard

Fill all three blanks to define a query 'getUser' that takes a non-nullable 'id' argument of type ID and returns a nullable 'User'.

GraphQL

type Query { getUser(id: [1]): [2] }

Drag options to blanks, or click blank then click option'

AID!

BUser

CUser!

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Making the return type non-nullable with an exclamation mark.

Using wrong argument type like String instead of ID.

The 'id' argument must be a non-nullable ID, so use ID!. The query returns a nullable User, so no exclamation mark after User.

Practice

1. What is the main purpose of schema linting in GraphQL?

easy

A. To generate database tables automatically

B. To execute queries faster

C. To check the schema for mistakes and style issues

D. To encrypt data in the schema

Solution

1. Step 1: Understand schema linting role

   Schema linting is used to find errors and style problems in GraphQL schemas.

2. Step 2: Compare with other options

   Options B, C, and D describe unrelated tasks like query speed, database creation, or encryption.

3. Final Answer:

   To check the schema for mistakes and style issues -> Option C

4. Quick Check:

   Schema linting = check mistakes and style [OK]

Hint: Linting means checking code or schema for errors [OK]

Common Mistakes:

• Confusing linting with query execution
• Thinking linting creates database tables
• Assuming linting encrypts data

2. Which of the following is a correct way to define a linting rule for a GraphQL schema?

easy

A. schemaLint: off

B. lintSchema = false

C. enableLinting = 0

D. "no-unused-types": true

Solution

1. Step 1: Identify correct lint rule syntax

   Linting rules are usually defined as key-value pairs like "no-unused-types": true.

2. Step 2: Check other options for syntax errors

   Options A, B, and D use invalid or incorrect syntax for linting rules.

3. Final Answer:

   "no-unused-types": true -> Option D

4. Quick Check:

   Lint rule syntax = key: value [OK]

Hint: Lint rules use key-value pairs like "rule-name": true [OK]

Common Mistakes:

• Using assignment (=) instead of key-value pairs
• Using invalid property names
• Turning off linting with wrong syntax

3. Given this linting configuration snippet:

{
  "no-deprecated-fields": true,
  "require-description": true
}

What will happen if the schema uses a deprecated field without a description?

medium

A. Linting will pass without errors

B. Linting will report errors for both deprecated field and missing description

C. Linting will only check for missing descriptions

D. Linting will ignore deprecated fields

Solution

1. Step 1: Analyze linting rules

   "no-deprecated-fields": true means deprecated fields cause errors. "require-description": true means missing descriptions cause errors.

2. Step 2: Apply rules to schema case

   Schema has a deprecated field without description, so both rules trigger errors.

3. Final Answer:

   Linting will report errors for both deprecated field and missing description -> Option B

4. Quick Check:

   Both rules active = errors for both issues [OK]

Hint: Active lint rules cause errors for matching schema issues [OK]

Common Mistakes:

• Assuming lint ignores deprecated fields
• Thinking only one rule applies
• Believing missing description is allowed

4. You run a schema linter and get an error: Field 'userAge' is missing a description. Which fix will resolve this error?

medium

A. Add a description string above the 'userAge' field in the schema

B. Rename the field to 'ageUser'

C. Remove the 'userAge' field from the schema

D. Ignore the error and continue

Solution

1. Step 1: Understand the error meaning

   The error says the field lacks a description, so the linter expects a comment or description string.

2. Step 2: Choose the fix that adds description

   Adding a description string above the field satisfies the linter. Renaming or removing the field or ignoring the error does not fix the missing description.

3. Final Answer:

   Add a description string above the 'userAge' field in the schema -> Option A

4. Quick Check:

   Missing description = add description [OK]

Hint: Add descriptions as comments to fix missing description errors [OK]

Common Mistakes:

• Renaming field instead of adding description
• Deleting field unnecessarily
• Ignoring lint errors

5. You want to enforce that all GraphQL schema types have descriptions and no unused types exist. Which combined linting configuration achieves this?

hard

A. { "require-description": true, "no-unused-types": true }

B. { "allow-unused-types": true, "require-description": false }

C. { "no-deprecated-fields": true, "allow-unused-types": false }

D. { "require-description": false, "no-unused-types": false }

Solution

1. Step 1: Identify rules for descriptions and unused types

   "require-description": true enforces descriptions. "no-unused-types": true disallows unused types.

2. Step 2: Match configuration to requirements

   { "require-description": true, "no-unused-types": true } sets both rules to true, matching the goal. Other options disable one or both rules.

3. Final Answer:

   { "require-description": true, "no-unused-types": true } -> Option A

4. Quick Check:

   Both rules true = enforce descriptions and no unused types [OK]

Hint: Set both rules true to enforce descriptions and no unused types [OK]

Common Mistakes:

• Disabling required rules
• Confusing allow and no rules
• Partial enforcement only