box-nestjs-monorepo/libs/common/src/interceptors/response.interceptor.ts

import {
  CallHandler,
  ExecutionContext,
  Injectable,
  NestInterceptor,
  StreamableFile,
} from '@nestjs/common';
import { map } from 'rxjs/operators';
import { ApiResponse } from '../interfaces/api-response.interface';

@Injectable()
export class ResponseInterceptor implements NestInterceptor {
  intercept(_context: ExecutionContext, next: CallHandler) {
    return next.handle().pipe(
      map((data): ApiResponse<unknown> | StreamableFile => {
        if (data instanceof StreamableFile) {
          return data;
        }

        return {
          error: '',
          status: 1,
          code: 'OK',
          data,
          timestamp: new Date().toISOString(),
        };
      }),
    );
  }
}