diff --git a/modules/openapi-generator/src/main/resources/typescript-nestjs/api.module.mustache b/modules/openapi-generator/src/main/resources/typescript-nestjs/api.module.mustache
index d3edaeb1f9c..636f9ef25f4 100644
--- a/modules/openapi-generator/src/main/resources/typescript-nestjs/api.module.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-nestjs/api.module.mustache
@@ -7,7 +7,7 @@ import { {{classname}} } from './{{importPath}}';
 {{/apis}}
 {{/apiInfo}}
 
-@Global
+@Global()
 @Module({
   imports:      [ HttpModule ],
   exports:      [
diff --git a/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache b/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache
index 6243cb7e09c..10e1dca34ed 100644
--- a/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-nestjs/api.service.mustache
@@ -1,16 +1,15 @@
 {{>licenseInfo}}
 /* tslint:disable:no-unused-variable member-ordering */
 
-import { HttpService, Inject, Injectable }                      from '@nestjs/common';
+import { HttpService, Inject, Injectable, Optional } from '@nestjs/common';
 import { AxiosResponse } from 'axios';
-import { Observable }                                        from 'rxjs';
+import { Observable } from 'rxjs';
 {{#imports}}
 import { {{classname}} } from '../{{filename}}';
 {{/imports}}
-import { Configuration }                                     from '../configuration';
-import { COLLECTION_FORMATS }                     from '../variables';
+import { Configuration } from '../configuration';
 {{#withInterfaces}}
-import { {{classname}}Interface }                            from './{{classFilename}}Interface';
+import { {{classname}}Interface } from './{{classFilename}}Interface';
 {{/withInterfaces}}
 
 {{#operations}}
@@ -32,9 +31,9 @@ export class {{classname}} {
     public defaultHeaders = new Map()
     public configuration = new Configuration();
 
-    constructor(protected httpClient: HttpService, configuration: Configuration) {
-        this.configuration = configuration;
-        this.basePath = basePath || configuration.basePath || this.basePath;
+    constructor(protected httpClient: HttpService, @Optional() configuration: Configuration) {
+        this.configuration = configuration || this.configuration;
+        this.basePath = configuration?.basePath || this.basePath;
     }
 
     /**
diff --git a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api.module.ts b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api.module.ts
index 8a1f505f16a..29ceb1d0f80 100644
--- a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api.module.ts
+++ b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api.module.ts
@@ -5,7 +5,7 @@ import { PetService } from './api/pet.service';
 import { StoreService } from './api/store.service';
 import { UserService } from './api/user.service';
 
-@Global
+@Global()
 @Module({
   imports:      [ HttpModule ],
   exports:      [
diff --git a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts
index 31f18b08201..1abb6e5121c 100644
--- a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts
+++ b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/pet.service.ts
@@ -11,13 +11,12 @@
  */
 /* tslint:disable:no-unused-variable member-ordering */
 
-import { HttpService, Inject, Injectable }                      from '@nestjs/common';
+import { HttpService, Inject, Injectable, Optional } from '@nestjs/common';
 import { AxiosResponse } from 'axios';
-import { Observable }                                        from 'rxjs';
+import { Observable } from 'rxjs';
 import { ApiResponse } from '../model/apiResponse';
 import { Pet } from '../model/pet';
-import { Configuration }                                     from '../configuration';
-import { COLLECTION_FORMATS }                     from '../variables';
+import { Configuration } from '../configuration';
 
 
 @Injectable()
@@ -27,9 +26,9 @@ export class PetService {
     public defaultHeaders = new Map()
     public configuration = new Configuration();
 
-    constructor(protected httpClient: HttpService, configuration: Configuration) {
-        this.configuration = configuration;
-        this.basePath = basePath || configuration.basePath || this.basePath;
+    constructor(protected httpClient: HttpService, @Optional() configuration: Configuration) {
+        this.configuration = configuration || this.configuration;
+        this.basePath = configuration?.basePath || this.basePath;
     }
 
     /**
diff --git a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/store.service.ts b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/store.service.ts
index fd616d69018..d2ce6fc8c2d 100644
--- a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/store.service.ts
+++ b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/store.service.ts
@@ -11,12 +11,11 @@
  */
 /* tslint:disable:no-unused-variable member-ordering */
 
-import { HttpService, Inject, Injectable }                      from '@nestjs/common';
+import { HttpService, Inject, Injectable, Optional } from '@nestjs/common';
 import { AxiosResponse } from 'axios';
-import { Observable }                                        from 'rxjs';
+import { Observable } from 'rxjs';
 import { Order } from '../model/order';
-import { Configuration }                                     from '../configuration';
-import { COLLECTION_FORMATS }                     from '../variables';
+import { Configuration } from '../configuration';
 
 
 @Injectable()
@@ -26,9 +25,9 @@ export class StoreService {
     public defaultHeaders = new Map()
     public configuration = new Configuration();
 
-    constructor(protected httpClient: HttpService, configuration: Configuration) {
-        this.configuration = configuration;
-        this.basePath = basePath || configuration.basePath || this.basePath;
+    constructor(protected httpClient: HttpService, @Optional() configuration: Configuration) {
+        this.configuration = configuration || this.configuration;
+        this.basePath = configuration?.basePath || this.basePath;
     }
 
     /**
diff --git a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/user.service.ts b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/user.service.ts
index 0bed28273bb..339b02d4650 100644
--- a/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/user.service.ts
+++ b/samples/client/petstore/typescript-nestjs-v6-provided-in-root/builds/default/api/user.service.ts
@@ -11,12 +11,11 @@
  */
 /* tslint:disable:no-unused-variable member-ordering */
 
-import { HttpService, Inject, Injectable }                      from '@nestjs/common';
+import { HttpService, Inject, Injectable, Optional } from '@nestjs/common';
 import { AxiosResponse } from 'axios';
-import { Observable }                                        from 'rxjs';
+import { Observable } from 'rxjs';
 import { User } from '../model/user';
-import { Configuration }                                     from '../configuration';
-import { COLLECTION_FORMATS }                     from '../variables';
+import { Configuration } from '../configuration';
 
 
 @Injectable()
@@ -26,9 +25,9 @@ export class UserService {
     public defaultHeaders = new Map()
     public configuration = new Configuration();
 
-    constructor(protected httpClient: HttpService, configuration: Configuration) {
-        this.configuration = configuration;
-        this.basePath = basePath || configuration.basePath || this.basePath;
+    constructor(protected httpClient: HttpService, @Optional() configuration: Configuration) {
+        this.configuration = configuration || this.configuration;
+        this.basePath = configuration?.basePath || this.basePath;
     }
 
     /**