bugfix(core): Allow circular structures for dynamic module nestjs#678

Author: BrunnerLivio

integration/injector/e2e/circular-structure-dynamic-modules.spec.ts

@@ -0,0 +1,16 @@
+import { expect } from 'chai';
+import { Test } from '@nestjs/testing';
+import { CircularModule } from '../src/circular-structure-dynamic-module/circular.module';
+import { InputService } from '../src/circular-structure-dynamic-module/input.service';
+
+describe('Circular structure for dynamic modules', () => {
+  it('should resolve circular structure with dynamic modules', async () => {
+    const builder = Test.createTestingModule({
+      imports: [CircularModule.forRoot()],
+    });
+    const testingModule = await builder.compile();
+    const inputService = testingModule.get<InputService>(InputService);
+
+    expect(inputService).to.be.instanceof(InputService);
+  });
+});

integration/injector/src/circular-structure-dynamic-module/circular.module.ts

@@ -0,0 +1,16 @@
+import { DynamicModule } from '@nestjs/common';
+import { InputService } from './input.service';
+
+export class CircularModule {
+  static forRoot(): DynamicModule {
+    const a = {
+      module: CircularModule,
+      providers: [
+        InputService,
+      ],
+      b: null,
+    };
+    a.b = a;
+    return a;
+  }
+}

integration/injector/src/circular-structure-dynamic-module/input.service.ts

@@ -0,0 +1,5 @@
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class InputService {
+}

packages/core/injector/module-token-factory.ts

@@ -2,6 +2,7 @@ import { DynamicModule } from '@nestjs/common';
 import { SHARED_MODULE_METADATA } from '@nestjs/common/constants';
 import { Type } from '@nestjs/common/interfaces/type.interface';
 import * as hash from 'object-hash';
+import safeStringify from 'fast-safe-stringify';
 
 export class ModuleTokenFactory {
   public create(
@@ -22,7 +23,9 @@ export class ModuleTokenFactory {
   public getDynamicMetadataToken(
     dynamicModuleMetadata: Partial<DynamicModule> | undefined,
   ): string {
-    return dynamicModuleMetadata ? JSON.stringify(dynamicModuleMetadata) : '';
+    // Uses safeStringify instead of JSON.stringify
+    // to support circular dynamic modules
+    return dynamicModuleMetadata ? safeStringify(dynamicModuleMetadata) : '';
   }
 
   public getModuleName(metatype: Type<any>): string {

packages/core/test/injector/module-token-factory.spec.ts

@@ -2,6 +2,7 @@ import { expect } from 'chai';
 import * as hash from 'object-hash';
 import { SingleScope } from '../../../common';
 import { ModuleTokenFactory } from '../../injector/module-token-factory';
+import safeStringify from 'fast-safe-stringify';
 
 describe('ModuleTokenFactory', () => {
   let factory: ModuleTokenFactory;
@@ -46,7 +47,7 @@ describe('ModuleTokenFactory', () => {
       expect(token).to.be.deep.eq(
         hash({
           module: Module.name,
-          dynamic: JSON.stringify({
+          dynamic: safeStringify({
             components: [{}],
           }),
           scope: [Module.name],