[FEAT] Add EnumFallback decorator

README.md

@@ -64,6 +64,12 @@ A package containing overriden class validators.
 
 See [the documentation here](./packages/class-validators).
 
+## NestJS class transformers
+
+A package containing custom class transformers.
+
+See [the documentation here](./packages/class-transformers).
+
 # Contribution
 
 This repository is managed by [Lerna.js](https://lerna.js.org). If you want to contribute, you need to follow these instructions:

package.json

@@ -89,12 +89,13 @@
     }
   },
   "dependencies": {
+    "@algoan/nestjs-class-transformers": "file:packages/class-transformers",
+    "@algoan/nestjs-class-validators": "file:packages/class-validators",
     "@algoan/nestjs-custom-decorators": "file:packages/custom-decorators",
     "@algoan/nestjs-google-pubsub-client": "file:packages/google-pubsub-client",
     "@algoan/nestjs-google-pubsub-microservice": "file:packages/google-pubsub-microservice",
     "@algoan/nestjs-http-exception-filter": "file:packages/http-exception-filter",
     "@algoan/nestjs-logging-interceptor": "file:packages/logging-interceptor",
-    "@algoan/nestjs-pagination": "file:packages/pagination",
-    "@algoan/nestjs-class-validators": "file:packages/class-validators"
+    "@algoan/nestjs-pagination": "file:packages/pagination"
   }
 }

packages/class-transformers/README.md

@@ -0,0 +1,29 @@
+# Nestjs class transformers
+
+A set of class transformers
+
+## Installation
+
+```bash
+npm install --save @algoan/nestjs-class-validators
+```
+
+## EnumFallback
+
+
+### Usage 
+
+```ts
+export enum UserRole {
+  ADMIN = 'ADMIN',
+  READER = 'READER',
+}
+
+class UserDto {
+  @EnumFallback({
+    type: UserRole,
+    fallback: (value: UserRole) => UserRole.READER // if the role is not "ADMIN" or "READER", then the role will be "READER". 
+  })
+  public role?: UserRole;
+}
+```

packages/class-transformers/jest.config.js

@@ -0,0 +1,8 @@
+module.exports = {
+    ...require('../jest.common'),
+
+    coverageDirectory: "coverage",
+    collectCoverageFrom: ["./src/**/*.ts"],
+
+    rootDir: ".",
+};

packages/class-transformers/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "@algoan/nestjs-class-transformers",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "build": "tsc -p .",
+    "test": "jest"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "class-transformer": "^0.5.1",
+    "class-validator": "^0.14.0",
+    "reflect-metadata": "^0.2.1"
+  },
+  "globals": {
+    "ts-jest": {
+      "diagnostics": false,
+      "isolatedModules": true
+    }
+  },
+  "peerDependencies": {
+    "@nestjs/common": ">=8"
+  }
+}

packages/class-transformers/src/enum-fallback.decorator.ts

@@ -0,0 +1,27 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+
+import { applyDecorators } from '@nestjs/common';
+import { Transform, TransformOptions } from 'class-transformer';
+
+/**
+ * Checks if a given value is the member of the provided enum and call a fallback function
+ * if the value is invalid
+ */
+interface EnumFallbackOptions<T> {
+  type: unknown;
+  fallback: (value: T) => T;
+}
+
+export function EnumFallback<T>(options: EnumFallbackOptions<T>, transformOptions?: TransformOptions) {
+  const { type, fallback } = options;
+
+  return applyDecorators(
+    Transform(({ value }) => {
+      if (value === undefined || !Object.values(type as string[]).includes(value)) {
+        return fallback(value);
+      }
+
+      return value;
+    }, transformOptions),
+  );
+}

packages/class-transformers/src/index.ts

@@ -0,0 +1 @@
+export * from './enum-fallback.decorator';

packages/class-transformers/test/enum-fallback-decorator.test.ts

@@ -0,0 +1,29 @@
+import { INestApplication } from '@nestjs/common';
+import { FakeAppController, UserRole, createTestAppModule } from './helpers';
+import * as request from 'supertest';
+
+describe('EnumFallback Decorator', () => {
+  let app: INestApplication;
+  let appController: FakeAppController;
+
+  beforeAll(async () => {
+    app = await createTestAppModule();
+    await app.init();
+  });
+  afterAll(async () => {
+    await app.close();
+  });
+
+  beforeEach(async () => {
+    appController = app.get<FakeAppController>(FakeAppController);
+  });
+
+  it('should apply the fallback functions when we have an invalid value', async () => {
+    const result = appController.createUser({ role: 'WRITER' as UserRole });
+    expect((result as { role: UserRole }).role).toEqual(UserRole.ADMIN);
+  });
+
+  it('should not apply the fallback function when the value is valid', async () => {
+    await request(app.getHttpServer()).post('/user').send({ role: 'READER' }).expect(201);
+  });
+});

packages/class-transformers/test/helpers.ts

@@ -0,0 +1,94 @@
+import {
+  Body,
+  Controller,
+  ExecutionContext,
+  INestApplication,
+  Logger,
+  Module,
+  Post,
+  ValidationPipe,
+} from '@nestjs/common';
+import { EnumFallback } from '../src';
+import { APP_GUARD } from '@nestjs/core';
+import { Test, TestingModule } from '@nestjs/testing';
+
+const fakeJWT: string =
+  'eyJhbGciOiJIUzI1NiIsInR5cCI6IddsqkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c';
+
+export enum UserRole {
+  ADMIN = 'ADMIN',
+  READER = 'READER',
+}
+
+export class UserDto {
+  private static readonly logger: Logger = new Logger(UserDto.name);
+
+  @EnumFallback({
+    type: UserRole,
+    fallback: (value: UserRole) => {
+      UserDto.logger.error(`Invalid user role ${value}`);
+      return UserRole.ADMIN;
+    },
+  })
+  public role?: UserRole;
+}
+
+/**
+ * Mock of the AuthGuard class
+ */
+class AuthGuardMock {
+  /**
+   * Check token
+   */
+  public canActivate(context: ExecutionContext): boolean {
+    const request: { user: { someId: string }; accessTokenJWT: string } = context.switchToHttp().getRequest();
+    request.user = {
+      someId: 'id',
+    };
+    request.accessTokenJWT = fakeJWT;
+    return true;
+  }
+}
+
+/**
+ * Test Controller
+ */
+@Controller()
+export class FakeAppController {
+  @Post('/user')
+  public createUser(@Body() user: UserDto): unknown {
+    console.log('[AL] user', user);
+    return user;
+  }
+}
+
+/**
+ * Fake app module
+ */
+/* eslint-disable */
+@Module({
+  controllers: [FakeAppController],
+  providers: [
+    {
+      provide: APP_GUARD,
+      useClass: AuthGuardMock,
+    },
+  ],
+})
+class AppModule {}
+/* eslint-enable */
+
+export async function createTestAppModule(): Promise<INestApplication> {
+  const moduleFixture: TestingModule = await Test.createTestingModule({
+    imports: [AppModule],
+  }).compile();
+  const app = moduleFixture.createNestApplication({});
+
+  app.useGlobalPipes(
+    new ValidationPipe({
+      whitelist: true,
+    }),
+  );
+
+  return app;
+}

packages/class-transformers/tsconfig.json

@@ -0,0 +1,15 @@
+{
+    "extends": "../tsconfig.base.json",
+    "compilerOptions": {
+      "declaration": true,
+      "experimentalDecorators": true,
+      "outDir": "dist",
+    },
+    "include": [
+      "./src/**/*",
+      "./test/**/*.ts"
+    ],
+    "exclude": [
+      "node_modules"
+    ]
+  }