refactor: code improvements

Author: Sairyss

.eslintrc.js

@@ -39,6 +39,7 @@ module.exports = {
     'import/no-cycle': 'off',
     'consistent-return': 'off',
     'no-underscore-dangle': 'off',
+    'max-classes-per-file': 'off',
 
     // Eslint errors
     'no-restricted-syntax': [

src/infrastructure/configs/app.routes.ts

@@ -1,4 +1,4 @@
-const usersRoot = '/user';
+const usersRoot = '/users';
 
 export const routes = {
   user: {

src/infrastructure/database/base-classes/typeorm.entity.base.ts

@@ -8,16 +8,16 @@ export abstract class TypeormEntityBase {
   }
 
   @PrimaryColumn({ update: false })
-  id!: string;
+  id: string;
 
   @CreateDateColumn({
     type: 'timestamptz',
     update: false,
   })
-  createdAt!: Date;
+  createdAt: Date;
 
   @UpdateDateColumn({
     type: 'timestamptz',
   })
-  updatedAt!: Date;
+  updatedAt: Date;
 }

src/interface-adapters/interfaces/user/create.user.interface.ts

@@ -1,3 +1,8 @@
+/*  Creating interfaces like this may be useful if you have a front end
+    web/mobile application or other microservices that need to talk to
+    your API since you can share them as a git submodule, a npm package/
+    library or in a monorepo.
+*/
 export interface CreateUser {
   email: string;
   country: string;

src/interface-adapters/interfaces/user/find-user-by-email.interface.ts

@@ -0,0 +1,5 @@
+export interface FindUsers {
+  readonly country: string;
+  readonly postalCode: string;
+  readonly street: string;
+}

src/interface-adapters/interfaces/user/find-users.interface.ts

@@ -5,7 +5,7 @@ import { createUserSymbol } from '@modules/user/user.providers';
 import { ApiOperation, ApiResponse } from '@nestjs/swagger';
 import { CreateUserCommand } from './create-user.command';
 import { CreateUserService } from './create-user.service';
-import { CreateUserRequest } from './create-user.request.dto';
+import { CreateUserHttpRequest } from './create-user.request.dto';
 
 @Controller()
 export class CreateUserHttpController {
@@ -27,7 +27,7 @@ export class CreateUserHttpController {
   @ApiResponse({
     status: HttpStatus.BAD_REQUEST,
   })
-  async create(@Body() body: CreateUserRequest): Promise<IdResponse> {
+  async create(@Body() body: CreateUserHttpRequest): Promise<IdResponse> {
     const command = new CreateUserCommand(body);
 
     const id = await this.createUser.createUser(command);

src/modules/user/commands/create-user/create-user.http.controller.ts

@@ -3,18 +3,18 @@ import { Inject } from '@nestjs/common';
 import { MessagePattern } from '@nestjs/microservices';
 import { IdResponse } from 'src/interface-adapters/dtos/id.response.dto';
 import { CreateUserCommand } from './create-user.command';
-import { CreateUserRequest } from './create-user.request.dto';
+import { CreateUserMessageRequest } from './create-user.request.dto';
 import { CreateUserService } from './create-user.service';
 
-export class CreateUserEventController {
+export class CreateUserMessageController {
   constructor(
     @Inject(createUserSymbol)
     private readonly createUser: CreateUserService,
   ) {}
 
-  @MessagePattern('user.create') // <- Subscribe to microservice event
-  async create(payload: CreateUserRequest): Promise<IdResponse> {
-    const command = new CreateUserCommand(payload);
+  @MessagePattern('user.create') // <- Subscribe to a microservice message
+  async create(message: CreateUserMessageRequest): Promise<IdResponse> {
+    const command = new CreateUserCommand(message);
 
     const id = await this.createUser.createUser(command);
 

src/modules/user/commands/create-user/create-user.event.controller.ts src/modules/user/commands/create-user/create-user.message.controller.ts

@@ -15,21 +15,27 @@ export class CreateUserRequest implements CreateUser {
   })
   @MaxLength(320)
   @IsEmail()
-  email!: string;
+  readonly email: string;
 
   @ApiProperty({ example: 'France', description: 'Country of residence' })
   @MaxLength(50)
   @IsString()
   @IsAlpha()
-  country!: string;
+  readonly country: string;
 
   @ApiProperty({ example: '28566', description: 'Postal code' })
   @MaxLength(10)
   @IsAlphanumeric()
-  postalCode!: string;
+  readonly postalCode: string;
 
   @ApiProperty({ example: 'Grande Rue', description: 'Street' })
   @MaxLength(50)
   @IsAlphanumeric()
-  street!: string;
+  readonly street: string;
 }
+
+export class CreateUserHttpRequest extends CreateUserRequest
+  implements CreateUser {}
+
+export class CreateUserMessageRequest extends CreateUserRequest
+  implements CreateUser {}

src/modules/user/commands/create-user/create-user.request.dto.ts

@@ -8,14 +8,14 @@ export class UserOrmEntity extends TypeormEntityBase {
   }
 
   @Column({ unique: true })
-  email!: string;
+  email: string;
 
   @Column()
-  country!: string;
+  country: string;
 
   @Column()
-  postalCode!: string;
+  postalCode: string;
 
   @Column()
-  street!: string;
+  street: string;
 }

src/modules/user/database/user.orm-entity.ts

@@ -14,6 +14,7 @@ import { QueryParams } from 'src/core/ports/repository.ports';
 import { UserOrmEntity } from './user.orm-entity';
 import { UserRepositoryPort } from './user.repository.interface';
 import { UserOrmMapper } from './user.orm-mapper';
+import { FindUsersQuery } from '../queries/find-users/find-users.query';
 
 @Injectable()
 export class UserRepository
@@ -58,6 +59,12 @@ export class UserRepository
     return false;
   }
 
+  async findUsers(query: FindUsersQuery): Promise<UserEntity[]> {
+    const users = await this.repository.find({ where: query });
+
+    return users.map(this.mapper.toDomainEntity);
+  }
+
   // Used to construct a query
   protected prepareQuery(
     params: QueryParams<UserProps>,
@@ -66,6 +73,18 @@ export class UserRepository
     if (params.id) {
       where.id = params.id.value;
     }
+    if (params.createdAt) {
+      where.createdAt = params.createdAt.value;
+    }
+    if (params.address?.country) {
+      where.country = params.address.country;
+    }
+    if (params.address?.street) {
+      where.street = params.address.street;
+    }
+    if (params.address?.postalCode) {
+      where.postalCode = params.address.postalCode;
+    }
     return where;
   }
 }

src/modules/user/database/user.repository.ts

@@ -43,3 +43,5 @@ export class UserResponse extends ResponseBase implements User {
   })
   street: string;
 }
+
+export class UserHttpResponse extends UserResponse implements User {}

src/modules/user/dtos/user.response.dto.ts

@@ -0,0 +1,27 @@
+import { Body, Controller, Get } from '@nestjs/common';
+import { routes } from '@config/app.routes';
+import { UserHttpResponse } from '@modules/user/dtos/user.response.dto';
+import { UserRepository } from '@modules/user/database/user.repository';
+import { FindUsersQuery } from './find-users.query';
+import { FindUsersHttpRequest } from './find-users.request.dto';
+
+@Controller()
+export class FindUsersHttpController {
+  constructor(private readonly userRepo: UserRepository) {}
+
+  /* Since this is a simple query with no additional business
+     logic involved, it bypasses application's core completely 
+     and retrieves user directly from repository.
+   */
+  @Get(routes.user.root)
+  async findUsers(
+    @Body() request: FindUsersHttpRequest,
+  ): Promise<UserHttpResponse[]> {
+    const query = new FindUsersQuery(request);
+    const users = await this.userRepo.findUsers(query);
+
+    /* Returning Response classes which are responsible
+       for whitelisting data that is sent to the user */
+    return users.map(user => new UserHttpResponse(user));
+  }
+}

src/modules/user/queries/find-user-by-email/find-user-by-email.http.controller.ts

@@ -0,0 +1,14 @@
+// Query is a plain object with properties
+export class FindUsersQuery {
+  constructor(props: FindUsersQuery) {
+    this.country = props.country;
+    this.postalCode = props.postalCode;
+    this.street = props.street;
+  }
+
+  readonly country: string;
+
+  readonly postalCode: string;
+
+  readonly street: string;
+}

src/modules/user/queries/find-user-by-email/find-user-by-email.request.dto.ts

@@ -0,0 +1,24 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { MaxLength, IsString, IsAlpha, IsAlphanumeric } from 'class-validator';
+import { FindUsers } from 'src/interface-adapters/interfaces/user/find-users.interface';
+
+export class FindUsersRequest implements FindUsers {
+  @ApiProperty({ example: 'France', description: 'Country of residence' })
+  @MaxLength(50)
+  @IsString()
+  @IsAlpha()
+  readonly country: string;
+
+  @ApiProperty({ example: '28566', description: 'Postal code' })
+  @MaxLength(10)
+  @IsAlphanumeric()
+  readonly postalCode: string;
+
+  @ApiProperty({ example: 'Grande Rue', description: 'Street' })
+  @MaxLength(50)
+  @IsAlphanumeric()
+  readonly street: string;
+}
+
+export class FindUsersHttpRequest extends FindUsersRequest
+  implements FindUsers {}

src/modules/user/queries/find-users/find-users.http.controller.ts

@@ -3,21 +3,21 @@ import { TypeOrmModule } from '@nestjs/typeorm';
 import { UserOrmEntity } from './database/user.orm-entity';
 import { UserRepository } from './database/user.repository';
 import { CreateUserHttpController } from './commands/create-user/create-user.http.controller';
-import { FindUserByEmailHttpController } from './queries/find-user-by-email/find-user-by-email.http.controller';
 import { DeleteUserHttpController } from './commands/delete-user/delete-user.controller';
 import {
   createUserCliLoggerProvider,
   createUserProvider,
   removeUserProvider,
 } from './user.providers';
 import { CreateUserCliController } from './commands/create-user/create-user.cli.controller';
+import { FindUsersHttpController } from './queries/find-users/find-users.http.controller';
 
 @Module({
   imports: [TypeOrmModule.forFeature([UserOrmEntity])],
   controllers: [
     CreateUserHttpController,
     DeleteUserHttpController,
-    FindUserByEmailHttpController,
+    FindUsersHttpController,
   ],
   providers: [
     UserRepository,

src/modules/user/queries/find-users/find-users.query.ts

@@ -7,6 +7,7 @@
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
     "allowSyntheticDefaultImports": true,
+    "strictPropertyInitialization": false,
     "target": "es2019",
     "sourceMap": true,
     "outDir": "./dist",