Code-first approach in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a GraphQL resolver using the code-first approach in NestJS.

NestJS

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

@Resolver()
export class SampleResolver {
  @Query(() => String)
  getHello() {
    return [1];
  }
}

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

A'Hello World!'

BHello World!

Creturn 'Hello World!'

Dconsole.log('Hello World!')

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string

Using console.log instead of returning a value

The query method should return a string value. Using a string literal like 'Hello World!' is correct.

2fill in blank

medium

Complete the code to define a GraphQL object type using the code-first approach.

NestJS

import { ObjectType, Field, Int } from '@nestjs/graphql';

@ObjectType()
export class [1] {
  @Field()
  name: string;

  @Field(() => Int)
  age: number;
}

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

AMutation

BUser

CResolver

DQuery

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Query' or 'Mutation' as object type names

Using decorator names as class names

The class name should represent the GraphQL object type. 'User' is a common example.

3fill in blank

hard

Fix the error in the code to correctly define a mutation using the code-first approach.

NestJS

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

@Resolver()
export class SampleResolver {
  @Mutation(() => Boolean)
  async updateName(@Args('name') [1]: string) {
    // update logic here
    return true;
  }
}

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

Aname

BName

CnewName

DupdateName

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase or different names than the @Args string

Mismatching argument names

The argument name in @Args decorator and the parameter name should match exactly and be lowercase.

4fill in blank

hard

Fill both blanks to create a GraphQL input type and use it in a mutation.

NestJS

import { InputType, Field } from '@nestjs/graphql';

@[1]()
export class UpdateUserInput {
  @Field()
  name: string;
}

@Resolver()
export class UserResolver {
  @Mutation(() => Boolean)
  async updateUser(@Args('[2]') input: UpdateUserInput) {
    // update logic
    return true;
  }
}

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

AInputType

BUpdateUserInput

CMutationInput

DUserInput

Attempts:

3 left

💡 Hint

Common Mistakes

Using @ObjectType instead of @InputType

Mismatching argument names in @Args

The class should be decorated with @InputType. The argument name in @Args should match the input class name.

5fill in blank

hard

Fill all three blanks to define a GraphQL resolver method that returns a list of users with proper decorators.

NestJS

import { Resolver, Query } from '@nestjs/graphql';
import { User } from './user.model';

@Resolver(() => User)
export class UserResolver {
  @Query(() => [[1]])
  async [2]() : Promise<[3][]> {
    // fetch users logic
    return [];
  }
}

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

AUser

Busers

DUserEntity

Attempts:

3 left

💡 Hint

Common Mistakes

Using singular method names for list queries

Mismatching return types and decorator types

The query returns a list of User objects. The method name is typically plural like 'users'. The return type is Promise of User array.