Queries and mutations in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a GraphQL query in NestJS.

NestJS

import { Query, Resolver } from '@nestjs/graphql';

@Resolver()
export class SampleResolver {
  @[1]()
  getHello(): string {
    return 'Hello World!';
  }
}

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

AMutation

BQuery

CSubscription

DController

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Mutation instead of @Query

Using @Controller which is for REST, not GraphQL

The @Query() decorator defines a GraphQL query method in NestJS.

2fill in blank

medium

Complete the code to define a GraphQL mutation in NestJS.

NestJS

import { Mutation, Resolver } from '@nestjs/graphql';

@Resolver()
export class SampleResolver {
  @[1]()
  createItem(): string {
    return 'Item created';
  }
}

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

AMutation

BQuery

CSubscription

DGet

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Query instead of @Mutation

Using @Get which is for REST controllers

The @Mutation() decorator defines a GraphQL mutation method in NestJS.

3fill in blank

hard

Fix the error in the resolver method decorator to correctly define a query.

NestJS

import { Query, Resolver } from '@nestjs/graphql';

@Resolver()
export class SampleResolver {
  @[1]()
  fetchData(): string {
    return 'Data fetched';
  }
}

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

AMutation

BSubscribe

CController

DQuery

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Mutation for a query method

Using @Subscribe which is not a valid decorator

To define a query, the method must use the @Query() decorator.

4fill in blank

hard

Fill both blanks to define a mutation method with an argument in NestJS GraphQL.

NestJS

import { Mutation, Resolver, Args } from '@nestjs/graphql';

@Resolver()
export class SampleResolver {
  @[1]()
  addUser(@[2]('name') name: string): string {
    return `User ${name} added`;
  }
}

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

AMutation

BQuery

CArgs

DParam

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Query instead of @Mutation

Using @Param which is for REST, not GraphQL

The @Mutation() decorator defines the mutation, and @Args() extracts the argument.

5fill in blank

hard

Fill all three blanks to define a query method with an argument and return type in NestJS GraphQL.

NestJS

import { Query, Resolver, Args } from '@nestjs/graphql';

@Resolver()
export class SampleResolver {
  @[1]()
  getUser(@[2]('id') id: string): [3] {
    return `User with ID ${id}`;
  }
}

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

AMutation

BArgs

Cstring

DQuery

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Mutation instead of @Query

Using @Param instead of @Args

Omitting the return type

The method is a query, so use @Query(). Arguments come from @Args(), and the return type is string.