generator-nest-js-boilerplate/generators/auth/templates/mongodb/oauth2/src/guards/is-logged.guard.ts

This generator will help you to build your own Nest.js Mongodb API using TypeScript 4

import {
  Injectable,
  CanActivate,
  ExecutionContext,
  UnauthorizedException,
} from '@nestjs/common';
import { Observable } from 'rxjs';

@Injectable()
export default class IsLoggedGuard implements CanActivate {
  canActivate(
    context: ExecutionContext,
  ): boolean | Promise<boolean> | Observable<boolean> {
    const req = context.switchToHttp().getRequest();

    if (req.isUnauthenticated()) {
      throw new UnauthorizedException('Login please');
    }

    return true;
  }
}