bugfix(@nestjs/core) exceptions passed in done() function, SyntaxError

src/core/router/routes-resolver.ts

@@ -10,7 +10,7 @@ import { MetadataScanner } from '../metadata-scanner';
 import { RouterExplorer } from './interfaces/explorer.inteface';
 import { ExpressRouterExplorer } from './router-explorer';
 import { ApplicationConfig } from './../application-config';
-import { NotFoundException } from '@nestjs/common';
+import { NotFoundException, BadRequestException } from '@nestjs/common';
 import { MODULE_PATH } from '@nestjs/common/constants';
 
 export class RoutesResolver implements Resolver {
@@ -43,8 +43,8 @@ export class RoutesResolver implements Resolver {
         : undefined;
       this.setupRouters(routes, moduleName, path, router);
     });
-
     this.setupNotFoundHandler(router);
+    this.setupExceptionHandler(router);
     this.setupExceptionHandler(express);
   }
 
@@ -79,7 +79,7 @@ export class RoutesResolver implements Resolver {
 
   public setupExceptionHandler(express: Application) {
     const callback = (err, req, res, next) => {
-      throw err;
+      throw this.mapExternalException(err);
     };
     const exceptionHandler = this.routerExceptionsFilter.create(
       {},
@@ -91,4 +91,13 @@ export class RoutesResolver implements Resolver {
     );
     express.use(proxy);
   }
+
+  public mapExternalException(err: any) {
+    switch (true) {
+      case (err instanceof SyntaxError): 
+        return new BadRequestException(err.message);
+      default: 
+        return err; 
+    }
+  }
 }

src/core/test/router/routes-resolver.spec.ts

@@ -5,6 +5,7 @@ import { Controller } from '../../../common/decorators/core/controller.decorator
 import { RequestMapping } from '../../../common/decorators/http/request-mapping.decorator';
 import { RequestMethod } from '../../../common/enums/request-method.enum';
 import { ApplicationConfig } from '../../application-config';
+import { BadRequestException } from '@nestjs/common';
 
 describe('RoutesResolver', () => {
   @Controller('global')
@@ -73,4 +74,23 @@ describe('RoutesResolver', () => {
       expect(spy.calledTwice).to.be.true;
     });
   });
+
+  describe('mapExternalExceptions', () => {
+    describe('when exception prototype is', () => {
+      describe('SyntaxError', () => {
+        it('should map to BadRequestException', () => {
+          const err = new SyntaxError();
+          const outputErr = routesResolver.mapExternalException(err);
+          expect(outputErr).to.be.instanceof(BadRequestException);
+        });
+      });
+      describe('other', () => {
+        it('should behave as an identity', () => {
+          const err = new Error();
+          const outputErr = routesResolver.mapExternalException(err);
+          expect(outputErr).to.be.eql(err);
+        });
+      });
+    });
+  });
 });