feat(common): support return type

nestjs · Aug 9, 2022 · a19a696 · a19a696
1 parent ebcf96a
commit a19a696
Showing 1 changed file with 31 additions and 8 deletions.
diff --git a/packages/common/serializer/class-serializer.interceptor.ts b/packages/common/serializer/class-serializer.interceptor.ts
@@ -1,8 +1,14 @@
+import { RETURN_TYPE_METADATA } from '../constants';
 import { Observable } from 'rxjs';
 import { map } from 'rxjs/operators';
 import { Inject, Injectable, Optional } from '../decorators/core';
 import { StreamableFile } from '../file-stream';
-import { CallHandler, ExecutionContext, NestInterceptor } from '../interfaces';
+import {
+  CallHandler,
+  ExecutionContext,
+  NestInterceptor,
+  Type,
+} from '../interfaces';
 import { ClassTransformOptions } from '../interfaces/external/class-transform-options.interface';
 import { TransformerPackage } from '../interfaces/external/transformer-package.interface';
 import { loadPackage } from '../utils/load-package.util';
@@ -23,6 +29,7 @@ const REFLECTOR = 'Reflector';
 export interface ClassSerializerInterceptorOptions
   extends ClassTransformOptions {
   transformerPackage?: TransformerPackage;
+  returnType?: Type<any>;
 }
 
 @Injectable()
@@ -45,15 +52,16 @@ export class ClassSerializerInterceptor implements NestInterceptor {
 
   intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
     const contextOptions = this.getContextOptions(context);
-    const options = {
+    const options: ClassSerializerInterceptorOptions = {
       ...this.defaultOptions,
       ...contextOptions,
     };
+    const returnType = this.getReturnType(context);
     return next
       .handle()
       .pipe(
         map((res: PlainLiteralObject | Array<PlainLiteralObject>) =>
-          this.serialize(res, options),
+          this.serialize(res, { returnType, ...options }),
         ),
       );
   }
@@ -63,7 +71,7 @@ export class ClassSerializerInterceptor implements NestInterceptor {
    */
   serialize(
     response: PlainLiteralObject | Array<PlainLiteralObject>,
-    options: ClassTransformOptions,
+    options: ClassSerializerInterceptorOptions,
   ): PlainLiteralObject | Array<PlainLiteralObject> {
     if (!isObject(response) || response instanceof StreamableFile) {
       return response;
@@ -76,11 +84,26 @@ export class ClassSerializerInterceptor implements NestInterceptor {
 
   transformToPlain(
     plainOrClass: any,
-    options: ClassTransformOptions,
+    options: ClassSerializerInterceptorOptions,
   ): PlainLiteralObject {
-    return plainOrClass
-      ? classTransformer.classToPlain(plainOrClass, options)
-      : plainOrClass;
+    if (!plainOrClass) {
+      return plainOrClass;
+    }
+    if (!options.returnType) {
+      return classTransformer.classToPlain(plainOrClass, options);
+    }
+    if (plainOrClass instanceof options.returnType) {
+      return classTransformer.classToPlain(plainOrClass, options);
+    }
+    const instance = classTransformer.plainToClass(
+      options.returnType,
+      plainOrClass,
+    );
+    return classTransformer.classToPlain(instance, options);
+  }
+
+  private getReturnType(context: ExecutionContext): Type<any> {
+    return this.reflector.get(RETURN_TYPE_METADATA, context.getHandler());
   }
 
   protected getContextOptions(