Post-Migration Checklist

After running tsgonest migrate --apply, follow this checklist to verify your project builds and runs correctly.

1. Install Dependencies

The migration adds tsgonest, @tsgonest/runtime, and @tsgonest/types to your package.json and removes old packages. Sync your lockfile:

npm install
# or
pnpm install
# or
yarn install

2. Review the Migration Report

Open tsgonest-migrate-report.md in your project root. Pay attention to:

• Manual TODOs — These items need human action. Common ones:
  • @Exclude() properties that need manual type restructuring
  • SwaggerModule.setup() calls to remove from main.ts
  • Custom validators (@MyValidator()) that need manual migration
  • Complex @Transform() patterns
  • tags.TagBase<> custom validators from Typia
• Warnings — Dependencies that were kept because they're still imported somewhere

3. Verify tsconfig.json

The migration removes baseUrl and compiler plugins. Check that:

• Path aliases still work — if you were using paths with baseUrl, the path mappings should still resolve via tsgonest's built-in path alias support
• No leftover ts-patch or typia plugin entries remain in compilerOptions.plugins

4. Verify tsgonest.config.ts

A tsgonest.config.ts file was generated with auto-detected settings:

import { defineConfig } from "@tsgonest/runtime";

export default defineConfig({
  controllers: { include: ["src/**/*.controller.ts"] },
  transforms: { validation: true, serialization: true },
  openapi: {
    output: "dist/openapi.json",
    // Security schemes auto-detected from @ApiBearerAuth, etc.
  },
});

Review the settings and adjust as needed. See Configuration for all options.

5. Remove SwaggerModule Setup

If your main.ts had Swagger UI setup, remove it:

// Remove all of this from main.ts:
const config = new DocumentBuilder()
  .setTitle('My API')
  .addBearerAuth()
  .build();
const document = SwaggerModule.createDocument(app, config);
SwaggerModule.setup('api', app, document);

tsgonest generates OpenAPI at build time. To serve the spec, configure openapi.output in tsgonest.config.ts and serve the generated JSON file statically or use a tool like Swagger UI pointed at the output file.

6. Remove Old Pipes and Interceptors

If you had validation pipes or serialization interceptors from Nestia or class-validator:

// Remove these from main.ts:
app.useGlobalPipes(new ValidationPipe({ transform: true }));
app.useGlobalInterceptors(new ClassSerializerInterceptor(app.get(Reflector)));

tsgonest injects validation and serialization at compile time — no runtime pipes or interceptors are needed for @Body(), @Query(), @Param(), and @Headers() parameters.

7. Build and Test

# Build with tsgonest
npx tsgonest build

# Or if scripts were updated:
npm run build

Fix any type errors that surface. Common issues:

Import errors after baseUrl removal

If you see module-not-found errors for bare imports like src/users/dto/user.dto, the migration should have rewritten these to relative paths. If any were missed:

// Change this:
import { UserDto } from 'src/users/dto/user.dto';

// To this:
import { UserDto } from '../users/dto/user.dto';

Entity files with class-validator decorators

Entity classes (@Entity(), @Schema(), etc.) are intentionally skipped by the migration. If you have class-validator decorators on entity properties, they'll remain. This is expected — entity validation is typically handled by the ORM, not by tsgonest.

Mapped types still importing from @nestjs/swagger

If OmitType, PickType, PartialType, or IntersectionType are your only imports from @nestjs/swagger, the migration rewrites the import source to @nestjs/mapped-types. Make sure @nestjs/mapped-types is installed:

npm install @nestjs/mapped-types

class-transformer still imported

If plainToInstance(), instanceToPlain(), or other runtime class-transformer utilities are still used in your code, the class-transformer package is kept in package.json. Remove the remaining usages manually if you want to fully uninstall it.

8. Run Your Test Suite

npm test

The migration changes DTOs from classes to interfaces, which may affect:

• Tests that use new CreateUserDto() — interfaces can't be instantiated. Use object literals instead:

  // Before
  const dto = new CreateUserDto();
  dto.email = 'test@example.com';
  
  // After
  const dto: CreateUserDto = { email: 'test@example.com', password: '123456' };

• Tests that use instanceof CreateUserDto — interfaces don't exist at runtime. Use type guards or duck typing instead.
• Tests that use plainToInstance(CreateUserDto, data) — replace with plain object assignment.

Next Steps

• Configuration Reference — Fine-tune tsgonest settings
• Validation — How tsgonest validates @Body(), @Query(), etc.
• OpenAPI — Configure OpenAPI generation
• Rules & Limitations — What tsgonest can and cannot analyze at compile time