Context setup in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a GraphQL context parameter in the resolver function.

GraphQL

const resolver = (parent, args, [1]) => { return args.id; }

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

Acontext

Binfo

Croot

Dparams

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'info' or 'root' instead of 'context' for shared data.

Confusing the order of resolver parameters.

The third parameter in a GraphQL resolver is usually called context. It holds shared data like authentication info.

2fill in blank

medium

Complete the code to access the user ID from the context inside a resolver.

GraphQL

const userId = [1].user.id;

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Aargs

Binfo

Cparent

Dcontext

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to get user ID from args or parent instead of context.

Using 'info' which holds query info, not user data.

The context object contains shared info like the authenticated user. Access user ID via context.user.id.

3fill in blank

hard

Fix the error in the resolver to correctly destructure context and get the database client.

GraphQL

const resolver = (parent, args, [1]) => { const { db } = context; return db.getUser(args.id); }

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Acontext

Bctx

Cinfo

Dparams

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different parameter name than the variable inside the function.

Not destructuring the context object properly.

The parameter name must match the variable used inside the function. Here, context is used, so it must be the parameter name.

4fill in blank

hard

Fill both blanks to correctly pass context to the Apollo Server constructor.

GraphQL

const server = new ApolloServer({ typeDefs, resolvers, [1]: () => ([2]) });

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Acontext

B{ user: currentUser }

Cschema

Dargs

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'schema' or 'args' instead of 'context' option.

Not returning an object from the context function.

The context option is a function returning an object with shared data like the current user.

5fill in blank

hard

Fill all three blanks to create a resolver that uses context to check user role and fetch data.

GraphQL

const resolver = (parent, args, [1]) => { if (![2].user || [3].user.role !== 'admin') { throw new Error('Unauthorized'); } return [2].db.getData(args.id); }

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

Acontext

Cctx

Dinfo

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing different names for context parameter.

Not checking if user exists before accessing role.

The resolver uses the context parameter (also called ctx sometimes) to check user info and access the database. Here, the same context object is used multiple times.