Why resolvers connect schema to data in GraphQL - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a resolver that returns a user's name.

GraphQL

const resolvers = { Query: { user: () => [1] } };

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Aname

B'Alice'

C{ name: 'Alice' }

Duser.name

Attempts:

3 left

💡 Hint

Common Mistakes

Returning a string instead of an object.

Using undefined variables.

The resolver must return an object matching the schema type. Here, it returns an object with a name property.

2fill in blank

medium

Complete the resolver to fetch a list of books from data.

GraphQL

const resolvers = { Query: { books: () => [1] } };

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AbookData

BgetBooks()

CfetchBooks

DbooksList

Attempts:

3 left

💡 Hint

Common Mistakes

Calling a function that is not defined.

Returning a function reference instead of data.

The resolver returns the variable booksList which holds the array of books.

3fill in blank

hard

Fix the error in the resolver to correctly return the user's email.

GraphQL

const resolvers = { User: { email: (parent) => [1] } };

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Aparent.email

Bparent.getEmail()

Cemail

Dparent.emailAddress

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong property name.

Calling a method that does not exist.

The resolver accesses the email property from the parent object, which holds the user data.

4fill in blank

hard

Fill both blanks to define a resolver that fetches a post by ID from data.

GraphQL

const resolvers = { Query: { post: (_, args) => [1].find(p => p.[2] === args.id) } };

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Aposts

BpostList

Cid

DpostId

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable or property names.

Mixing up argument and property names.

The resolver searches the posts array for a post where the id matches the argument args.id.

5fill in blank

hard

Fill all three blanks to create a resolver that returns the titles of all books published after a given year.

GraphQL

const resolvers = { Query: { recentBooks: (_, args) => [1].filter(book => book.[2] > args.[3]).map(book => book.title) } };

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

Abooks

BpublishedYear

Cyear

DpublishDate

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect property or argument names.

Not chaining filter and map correctly.

The resolver filters the books array for books with publishedYear greater than the argument year, then maps to their titles.