SmartHomeWithoutCommand.JS

// Receiver: Lamp
class Lamp {
  turnOn() {
    console.log("Lamp is ON");
  }

  turnOff() {
    console.log("Lamp is OFF");
  }
}

// Smart Home Controller (Tightly Coupled)
class SmartHomeController {
  constructor(lamp) {
    this.lamp = lamp;
    this.history = [];
  }

  turnOnLamp() {
    this.lamp.turnOn();
    this.history.push(() => this.lamp.turnOff());
  }

  turnOffLamp() {
    this.lamp.turnOff();
    this.history.push(() => this.lamp.turnOn());
  }

  pressUndo() {
    const undo = this.history.pop();
    if (undo) undo();
  }
}

// Usage
const lamp = new Lamp();
const controller = new SmartHomeController(lamp);

controller.turnOnLamp();  // Lamp is ON
controller.turnOffLamp(); // Lamp is OFF

controller.pressUndo();   // Lamp is ON
controller.pressUndo();   // Lamp is OFF