import { ExtractJwt, Strategy } from 'passport-jwt';

import { AuthService } from './auth.service';

import { PassportStrategy } from '@nestjs/passport';

import { Injectable, UnauthorizedException } from '@nestjs/common';

import { JwtPayload } from './model/jwt-payload.model';



@Injectable()

export class JwtStrategy extends PassportStrategy(Strategy) {

  constructor(private readonly authService: AuthService) {

    super({

      jwtFromRequest: ExtractJwt.fromAuthHeaderAsBearerToken(),

      secretOrKey: 'secretKey',

    });

  }



  async validate(payload: JwtPayload) {

    const user = await this.authService.validateUser(payload);

    if (!user) {

      throw new UnauthorizedException();

    }

    return true;

  }

}

Token is extracted from the request by PassportStrategy. I don't know how to catch the error when the token expires or gets invalid. My purpose is if there is an error because the token expired, I need to refresh the token. Otherwise do something else.