In NestJS framework, I have an array of object, each object contains an instance of my car class, this class have a lot of public and private property and some method. Since my project doesn’t have any database except Redis and sometimes restart unexpectedly; I want to store this array of object into Redis DB every one minute.

My main TypeScript file is like this:

    class car {
        public name ;
        private model;
        constructor(car_name){
            this.name = car_name;
        }
        start() {
            console.log(this.name + ' start the engine');
        }
    }

    let myBMW = new car('bmw');
    let myNISSAN = new car('nissan');

    let arr_of_obj = [
        {
            name : "bmw",
            type : "racing",
            mymethod : myBMW
        },
        {
            name : "nissan",
            type : "sedan",
            mymethod : myNISSAN
        }
    ];

and my Redis service is:

import { Inject, Injectable } from '@nestjs/common';
import Redis from 'ioredis';


@Injectable()
export class RedisDbService {
  constructor(@Inject('REDIS_CLIENT') private readonly redisClient: Redis) {}

  async set(key: string, value: any, ex: number) {
    return await this.redisClient.set(key, JSON.stringify(value), 'EX', ex);
  }

  async get(key: string) {
    const data = await this.redisClient.get(key);
    if(data == null){
      return [];
    }
    return JSON.parse(data);
  }

  async deletekey(key: string) {
    return this.redisClient.del(key);
  }
}

So, when I use this line of codes I get error start() is not a function:

this.redisService.set('car_in_redis', myBMW , 300);
let new_car = await this.redisService.get('car_in_redis');
new_car.start();

I know the JSON.stringify() and JSON.parse() is the reason but how to store an instance completely inside Redis?