#状态模式(State)

/*
state
0 销售中
1 订单成功
2 商品转到物流
3 物流发送
*/
class System {
  constructor() {
    this.state = 0;
  }
  setState(state) {
    this.state = state;
  }
}

class Sales {
  constructor() {}
  confirmOrder(target) {
    target.state == 1 ? target.setState(2) : "";
  }
}

class Logistics {
  constructor() {}
  complet(target) {
    target.state == 2 ? target.setState(3) : "";
  }
}

class Client {
  constructor() {}
  buy(target) {
    target.state == 0 ? target.setState(1) : "";
  }
}

export { System, Sales, Logistics, Client };

let system = new System();
let client = new Client("julong");
let sales = new Sales("sale1");
let logistics = new Logistics("l1");
client.buy(system);
sales.confirmOrder(system);
logistics.complet(system);