Resolver chains in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

GraphQL

const resolvers = {
  Query: {
    user: (parent, args, context, info) => [1]
  }
};

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

Aparent.name

Bcontext.db.getUserName()

Cargs.id

Dinfo.fieldName

Attempts:

3 left

💡 Hint

Common Mistakes

Using args.id instead of parent.name

Trying to access context without it being passed

The resolver function accesses the parent object to get the user's name.

2fill in blank

medium

Complete the resolver chain to fetch the user's posts from the database.

GraphQL

const resolvers = {
  User: {
    posts: (parent, args, context) => [1]
  }
};

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

Aparent.posts

Bcontext.db.getPostsByUserId(parent.id)

Cargs.posts

Dcontext.posts

Attempts:

3 left

💡 Hint

Common Mistakes

Using parent.posts which may not be populated

Using args.posts which is incorrect

The resolver uses the context to access the database and fetch posts by the user's ID.

3fill in blank

hard

Fix the error in the resolver chain to correctly resolve the user's profile picture URL.

GraphQL

const resolvers = {
  User: {
    profilePicture: (parent, args, context) => {
      return context.storage.getUrl([1]);
    }
  }
};

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

Acontext.userId

Bargs.profilePicId

Cparent.id

Dparent.profilePicId

Attempts:

3 left

💡 Hint

Common Mistakes

Using args.profilePicId which is not passed

Using parent.id which is the user ID, not picture ID

The resolver should use the profilePicId from the parent object to get the URL.

4fill in blank

hard

Fill both blanks to create a resolver chain that fetches comments for a post and filters by author ID.

GraphQL

const resolvers = {
  Post: {
    comments: (parent, args, context) => {
      return context.db.getCommentsByPostId(parent.[1]).filter(comment => comment.[2] === args.authorId);
    }
  }
};

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Aid

BpostId

CauthorId

DuserId

Attempts:

3 left

💡 Hint

Common Mistakes

Using parent.postId which does not exist

Filtering by comment.userId instead of authorId

The post's ID is parent.id, and comments have an authorId to filter by.

5fill in blank

hard

Fill all three blanks to create a resolver chain that fetches a user's friends and maps their names.

GraphQL

const resolvers = {
  User: {
    friendsNames: async (parent, args, context) => {
      const friends = await context.db.getFriendsByUserId(parent.[1]);
      return friends.map(friend => friend.[2]).filter(name => name [3] '');
    }
  }
};

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

Aid

BuserId

Cname

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using userId instead of id

Mapping friend.userId instead of friend.name

Using == instead of !== for filtering

The resolver uses parent.id to get friends, maps their name, and filters out empty names using !==.