nest_custom_logger_interceptor.ts

import { Injectable, NestInterceptor, ExecutionContext, CallHandler } from '@nestjs/common';
import { Observable } from 'rxjs';
import { tap } from 'rxjs/operators';

@Injectable()
export class LoggingInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    console.log('Before handler execution');
    const startTime = new Date();
    // Proceed with the request and log the response
    return next.handle().pipe(
      map((data)=> ({data:data, timeToCompletion: `${new Date() - startTime} ms` })),
      tap(() => console.log('After handler execution'))
    );
  }
}