Class Vehicle_Obj Classess_

  class Vehicle {
    constructor( type, model, parts, fuel, ){
      this.type = type;
      this.model = model;
      this.parts = parts; // parts is object
      this.fuel = fuel;
      this.parts.quality = this.parts.engine * this.parts.power;
    }

    drive (fuelLoss){
     this.fuel -= fuelLoss;
    }
}

let parts = { engine: 6, power: 100 };
let vehicle = new Vehicle('a', 'b', parts, 200);
vehicle.drive(100);
console.log(vehicle.fuel);
console.log(vehicle.parts.quality);