feature(@nestjs/core) add @Optional() decorator #847

packages/common/constants.ts

@@ -12,6 +12,7 @@ export const GLOBAL_MODULE_METADATA = '__globalModule__';
 export const PATH_METADATA = 'path';
 export const PARAMTYPES_METADATA = 'design:paramtypes';
 export const SELF_DECLARED_DEPS_METADATA = 'self:paramtypes';
+export const OPTIONAL_DEPS_METADATA = 'optional:paramtypes';
 export const METHOD_METADATA = 'method';
 export const ROUTE_ARGS_METADATA = '__routeArguments__';
 export const CUSTOM_ROUTE_AGRS_METADATA = '__customRouteArgs__';

packages/common/decorators/core/index.ts

@@ -1,11 +1,12 @@
-export * from './controller.decorator';
-export * from './component.decorator';
-export * from './dependencies.decorator';
-export * from './inject.decorator';
-export * from './catch.decorator';
-export * from './exception-filters.decorator';
-export * from './use-pipes.decorator';
-export * from './use-guards.decorator';
-export * from './reflect-metadata.decorator';
-export * from './use-interceptors.decorator';
 export * from './bind.decorator';
+export * from './catch.decorator';
+export * from './component.decorator';
+export * from './controller.decorator';
+export * from './dependencies.decorator';
+export * from './exception-filters.decorator';
+export * from './inject.decorator';
+export * from './optional.decorator';
+export * from './reflect-metadata.decorator';
+export * from './use-guards.decorator';
+export * from './use-interceptors.decorator';
+export * from './use-pipes.decorator';

packages/common/decorators/core/optional.decorator.ts

@@ -0,0 +1,12 @@
+import 'reflect-metadata';
+import { OPTIONAL_DEPS_METADATA } from '../../constants';
+
+/**
+ * Sets dependency as an optional one.
+ */
+export function Optional(): ParameterDecorator {
+  return (target, key, index) => {
+    const args = Reflect.getMetadata(OPTIONAL_DEPS_METADATA, target) || [];
+    Reflect.defineMetadata(OPTIONAL_DEPS_METADATA, [...args, index], target);
+  };
+}

packages/common/index.ts

@@ -7,39 +7,39 @@
 
 export * from './decorators';
 export * from './enums';
-export {
-  NestModule,
-  INestApplication,
-  INestMicroservice,
-  NestMiddleware,
-  MiddlewareFunction,
-  MiddlewareConsumer,
-  OnModuleInit,
-  ExceptionFilter,
-  WebSocketAdapter,
-  PipeTransform,
-  Paramtype,
-  ArgumentMetadata,
-  OnModuleDestroy,
-  ExecutionContext,
-  CanActivate,
-  RpcExceptionFilter,
-  WsExceptionFilter,
-  NestInterceptor,
-  DynamicModule,
-  INestApplicationContext,
-  HttpServer,
-  Provider,
-  Type,
-  HttpServerFactory,
-  ArgumentsHost,
-  INestExpressApplication,
-  INestFastifyApplication,
-  ForwardReference,
-} from './interfaces';
-export * from './interceptors';
-export * from './services/logger.service';
-export * from './pipes';
-export * from './utils';
 export * from './exceptions';
 export * from './http';
+export * from './interceptors';
+export {
+  ArgumentMetadata,
+  ArgumentsHost,
+  CanActivate,
+  DynamicModule,
+  ExceptionFilter,
+  ExecutionContext,
+  ForwardReference,
+  HttpServer,
+  HttpServerFactory,
+  INestApplication,
+  INestApplicationContext,
+  INestExpressApplication,
+  INestFastifyApplication,
+  INestMicroservice,
+  MiddlewareConsumer,
+  MiddlewareFunction,
+  NestInterceptor,
+  NestMiddleware,
+  NestModule,
+  OnModuleDestroy,
+  OnModuleInit,
+  Paramtype,
+  PipeTransform,
+  Provider,
+  RpcExceptionFilter,
+  Type,
+  WebSocketAdapter,
+  WsExceptionFilter,
+} from './interfaces';
+export * from './pipes';
+export * from './services/logger.service';
+export * from './utils';

packages/common/pipes/validation.pipe.ts

@@ -1,3 +1,4 @@
+import { Optional } from '../decorators';
 import { ArgumentMetadata, BadRequestException } from '../index';
 import { ValidatorOptions } from '../interfaces/external/validator-options.interface';
 import { PipeTransform } from '../interfaces/features/pipe-transform.interface';
@@ -19,7 +20,7 @@ export class ValidationPipe implements PipeTransform<any> {
   protected isDetailedOutputDisabled: boolean;
   protected validatorOptions: ValidatorOptions;
 
-  constructor(options?: ValidationPipeOptions) {
+  constructor(@Optional() options?: ValidationPipeOptions) {
     options = options || {};
     const { transform, disableErrorMessages, ...validatorOptions } = options;
     this.isTransformEnabled = !!transform;

packages/core/injector/injector.ts

@@ -1,4 +1,4 @@
-import { PARAMTYPES_METADATA, SELF_DECLARED_DEPS_METADATA } from '@nestjs/common/constants';
+import { OPTIONAL_DEPS_METADATA, PARAMTYPES_METADATA, SELF_DECLARED_DEPS_METADATA } from '@nestjs/common/constants';
 import { Controller } from '@nestjs/common/interfaces/controllers/controller.interface';
 import { Injectable } from '@nestjs/common/interfaces/injectable.interface';
 import { Type } from '@nestjs/common/interfaces/type.interface';
@@ -99,7 +99,7 @@ export class Injector {
     await this.loadInstance<Injectable>(wrapper, components, module);
   }
 
-  public applyDoneSubject<T>(wrapper: InstanceWrapper<T>): () => void {
+  public applyDoneHook<T>(wrapper: InstanceWrapper<T>): () => void {
     let done: () => void;
     wrapper.done$ = new Promise<void>((resolve, reject) => {
       done = resolve;
@@ -116,13 +116,15 @@ export class Injector {
     if (wrapper.isPending) {
       return await wrapper.done$;
     }
-    const done = this.applyDoneSubject(wrapper);
+    const done = this.applyDoneHook(wrapper);
     const { metatype, name, inject } = wrapper;
     const currentMetatype = collection.get(name);
     if (isUndefined(currentMetatype)) {
       throw new RuntimeException();
     }
-    if (currentMetatype.isResolved) return null;
+    if (currentMetatype.isResolved) {
+      return void 0;
+    }
 
     await this.resolveConstructorParams<T>(
       wrapper,
@@ -153,22 +155,34 @@ export class Injector {
     callback: (args) => void,
   ) {
     let isResolved = true;
+
     const dependencies = isNil(inject)
       ? this.reflectConstructorParams(wrapper.metatype)
       : inject;
+    const optionalDependenciesIds = isNil(inject)
+      ? this.reflectOptionalParams(wrapper.metatype)
+      : [];
 
     const instances = await Promise.all(
       dependencies.map(async (param, index) => {
-        const paramWrapper = await this.resolveSingleParam<T>(
-          wrapper,
-          param,
-          { index, dependencies },
-          module,
-        );
-        if (!paramWrapper.isResolved && !paramWrapper.forwardRef) {
-          isResolved = false;
+        try {
+          const paramWrapper = await this.resolveSingleParam<T>(
+            wrapper,
+            param,
+            { index, dependencies },
+            module,
+          );
+          if (!paramWrapper.isResolved && !paramWrapper.forwardRef) {
+            isResolved = false;
+          }
+          return paramWrapper.instance;
+        } catch (err) {
+          const isOptional = optionalDependenciesIds.includes(index);
+          if (!isOptional) {
+            throw err;
+          }
+          return null;
         }
-        return paramWrapper.instance;
       }),
     );
     isResolved && (await callback(instances));
@@ -182,6 +196,10 @@ export class Injector {
     return paramtypes;
   }
 
+  public reflectOptionalParams<T>(type: Type<T>): any[] {
+    return Reflect.getMetadata(OPTIONAL_DEPS_METADATA, type) || [];
+  }
+
   public reflectSelfParams<T>(type: Type<T>): any[] {
     return Reflect.getMetadata(SELF_DECLARED_DEPS_METADATA, type) || [];
   }
@@ -313,4 +331,4 @@ export class Injector {
     };
     return modules.concat.apply(modules, modules.map(flatten));
   }
-}
+}

packages/core/test/injector/injector.spec.ts

@@ -101,7 +101,7 @@ describe('Injector', () => {
       expect(result).to.be.eql(value);
     });
 
-    it('should return null when metatype is resolved', async () => {
+    it('should return undefined when metatype is resolved', async () => {
       const value = 'test';
       const result = await injector.loadInstance(
         {
@@ -113,7 +113,7 @@ describe('Injector', () => {
         moduleDeps.components,
         moduleDeps,
       );
-      expect(result).to.be.null;
+      expect(result).to.be.undefined;
     });
   });
 

tsconfig.json

@@ -11,7 +11,10 @@
     "target": "es6",
     "sourceMap": true,
     "allowJs": true,
-    "outDir": "dist"
+    "outDir": "dist",
+    "lib": [
+      "es7"
+    ]
   },
   "include": [
     "packages/**/*",