CODEWITHSUNDEEP
typescriptnestjsnestinterceptor
Renato Cassino
Renato Cassino

Reputation: 840

Cannot use Eeflector in custom interceptor on nestjs. Cannot import module

I'm creating an interceptor for my NestJs application. I want to add some metadata to my controller method and get this value in my interceptor.

A did my interceptor and my custom decorator to add metadata, but when I try to get the Reflector in my interceptor constructor I receive an error that I cannot solve.

My interceptor:

@Injectable()
export class MyCustomInterceptor implements CacheInterceptor {
  private reflector: Reflector;

  constructor(reflector: Reflector) {
    this.reflector = reflector;
  }

  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const myReflectionData = this.reflector.get<string[]>('mykey', context.getHandler());
  //...

My custom decorator:

import { applyDecorators, SetMetadata } from '@nestjs/common';

export const MyCustomDecorator = (listOfData: Array<string>) => applyDecorators(
  SetMetadata('mykey', listOfData),
);


  @MyCustomDecorator(['data1', 'data2'])
  @UseInterceptors(MyCustomInterceptor)
  @Get()
  async listMyData(
    @Query('limit') limit = 10,
    @Query('skip') skip = '',
    @Query('orderBy') orderBy = 'id',
    @Query('sort') sort = 'DESC',
  ) {
    // .....

With this code I receive this error:

[Nest] 10911  - 07/03/2022, 11:09:29 PM   ERROR [ExceptionHandler] Nest can't resolve dependencies of the MyCustomInterceptor (?). Please make sure that the argument Reflector at index [0] is available in the CommunitiesModule context.

Potential solutions:
- If Reflector is a provider, is it part of the current MyAppModule?
- If Reflector is exported from a separate @Module, is that module imported within MyAppModule?
  @Module({
    imports: [ /* the Module containing Reflector */ ]
  })

Error: Nest can't resolve dependencies of the MyCustomInterceptor (?). Please make sure that the argument Reflector at index [0] is available in the MyAppModule context.

Potential solutions:
- If Reflector is a provider, is it part of the current MyAppModule?
- If Reflector is exported from a separate @Module, is that module imported within MyAppModule?
  @Module({
    imports: [ /* the Module containing Reflector */ ]
  })

    at Injector.lookupComponentInParentModules (/.../node_modules/@nestjs/core/injector/injector.js:202:19)
    at Injector.resolveComponentInstance (/.../node_modules/@nestjs/core/injector/injector.js:157:33)
    at resolveParam (/.../node_modules/@nestjs/core/injector/injector.js:108:38)
    at async Promise.all (index 0)
    at Injector.resolveConstructorParams (/.../node_modules/@nestjs/core/injector/injector.js:123:27)
    at Injector.loadInstance (/.../node_modules/@nestjs/core/injector/injector.js:52:9)
    at Injector.loadProvider (/.../node_modules/@nestjs/core/injector/injector.js:74:9)
    at async Promise.all (index 8)
    at InstanceLoader.createInstancesOfProviders (/.../node_modules/@nestjs/core/injector/instance-loader.js:44:9)
    at /.../node_modules/@nestjs/core/injector/instance-loader.js:29:13

I tried to add Reflector to imports and providers in my .module.ts, but didn't work :/

How can I do to solve?

Thanks for this

Upvotes: 1

Views: 1565

Answers (1)

Cody Tseng
Cody Tseng

Reputation: 398

@Injectable()
export class MyCustomInterceptor implements CacheInterceptor {
  constructor(private reflector: Reflector) {}

  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const myReflectionData = this.reflector.get<string[]>('mykey', context.getHandler());
  //...

Or:

@Injectable()
export class MyCustomInterceptor implements CacheInterceptor {
  @Inject() private reflector: Reflector;

  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const myReflectionData = this.reflector.get<string[]>('mykey', context.getHandler());
  //...

Upvotes: 4

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