feat: take full control over non-http exceptions

src/main.ts

@@ -1,13 +1,14 @@
 import 'source-map-support/register';
 
-import { NestFactory, Reflector } from '@nestjs/core';
+import { HttpAdapterHost, NestFactory, Reflector } from '@nestjs/core';
 import { ClassSerializerInterceptor, ValidationPipe } from '@nestjs/common';
 import { useContainer } from 'class-validator';
 
 import { AppModule } from './modules/main/app.module';
 import { setupSwagger } from './swagger';
 import { TrimStringsPipe } from './modules/common/pipe/trim-strings.pipe';
 import { APP_PORT, TOTAL_COUNT_HEADER_KEY } from './constants';
+import { AllExceptionsFilter } from './modules/common/exception-filter/all-exceptions.filter';
 
 declare const module: any;
 
@@ -29,6 +30,9 @@ async function bootstrap() {
 
   useContainer(app.select(AppModule), { fallbackOnErrors: true });
 
+  const httpAdapter = app.get(HttpAdapterHost);
+  app.useGlobalFilters(new AllExceptionsFilter(httpAdapter));
+
   await app.listen(APP_PORT);
 
   if (module.hot) {

src/modules/common/exception-filter/all-exceptions.filter.ts

@@ -0,0 +1,53 @@
+import {
+  ExceptionFilter,
+  Catch,
+  ArgumentsHost,
+  HttpException,
+  HttpStatus,
+} from '@nestjs/common';
+import { HttpAdapterHost } from '@nestjs/core';
+import { QueryFailedError } from 'typeorm';
+
+type ResponseBody = {
+  statusCode: number;
+  message: string | string[];
+  error: string;
+};
+
+@Catch()
+export class AllExceptionsFilter implements ExceptionFilter {
+  constructor(private readonly httpAdapterHost: HttpAdapterHost) {}
+
+  catch(exception: unknown, host: ArgumentsHost): void {
+    // In certain situations `httpAdapter` might not be available in the
+    // constructor method, thus we should resolve it here.
+    const { httpAdapter } = this.httpAdapterHost;
+
+    const ctx = host.switchToHttp();
+
+    let statusCode: number;
+    let responseBody: ResponseBody;
+
+    // We now handle both HTTP and non-HTTP errors comprehensively.
+    if (exception instanceof HttpException) {
+      statusCode = exception.getStatus();
+      responseBody = exception.getResponse() as ResponseBody;
+    } else if (exception instanceof QueryFailedError) {
+      statusCode = HttpStatus.BAD_REQUEST;
+      responseBody = {
+        statusCode,
+        message: exception.message,
+        error: 'Database Query Failed Error',
+      };
+    } else {
+      statusCode = HttpStatus.INTERNAL_SERVER_ERROR;
+      responseBody = {
+        statusCode,
+        message: (exception as Error).message,
+        error: 'Internal Server Error',
+      };
+    }
+
+    httpAdapter.reply(ctx.getResponse(), responseBody, statusCode);
+  }
+}