Repository pattern in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Repository class from TypeORM.

NestJS

import { [1] } from 'typeorm';

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AModule

BRepository

CController

DService

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Service or Controller instead of Repository.

Forgetting to import from 'typeorm'.

The Repository class is imported from typeorm to use the repository pattern in NestJS.

2fill in blank

medium

Complete the code to inject the repository for the User entity using @InjectRepository.

NestJS

constructor(@InjectRepository([1]) private userRepository: Repository<User>) {}

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AUser

BUserService

CUserModule

DUserController

Attempts:

3 left

💡 Hint

Common Mistakes

Passing service or module names instead of the entity class.

Omitting the entity class inside @InjectRepository.

The @InjectRepository decorator takes the entity class, here User, to inject its repository.

3fill in blank

hard

Fix the error in the method to find a user by id using the repository.

NestJS

async findUserById(id: number): Promise<User | null> {
  return await this.userRepository.[1]({ id });
}

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AfindOneById

BfindById

CfindOne

DgetOne

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like findOneById or findById.

Using getOne which is not a repository method.

The correct method to find one entity by id in TypeORM repository is findOne.

4fill in blank

hard

Fill both blanks to create a new user entity and save it using the repository.

NestJS

const newUser = this.userRepository.[1](userData);
await this.userRepository.[2](newUser);

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Acreate

Bsave

Cinsert

Dupdate

Attempts:

3 left

💡 Hint

Common Mistakes

Using insert instead of save after create.

Using update instead of save for new entities.

Use create to make a new entity instance and save to store it in the database.

5fill in blank

hard

Fill all three blanks to update a user's email by id using the repository.

NestJS

await this.userRepository.[1]({ id: userId }, { [2]: [3] });

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Aupdate

Bemail

CnewEmail

Dsave

Attempts:

3 left

💡 Hint

Common Mistakes

Using save instead of update for partial updates.

Mixing up field names or values in the update object.

The update method takes a condition object and a partial entity with fields to update. Here, we update the email field to newEmail.