ES6 +角度控制器类，在回调中未定义

class AngleController {
  constructor() {
    this.angle = 0;
  }

  rotate(degrees) {
    this.angle += degrees;
    console.log(`Rotated by ${degrees} degrees. Current angle: ${this.angle}`);
  }
}

const controller = new AngleController();
controller.rotate(90); // Rotated by 90 degrees. Current angle: 90

// 模拟异步操作，例如使用setTimeout
setTimeout(() => {
  controller.rotate(180); // Rotated by 180 degrees. Current angle: 270
}, 1000);

// 在回调中未定义的示例
setTimeout(() => {
  // 在回调中未定义的变量
  console.log(undefinedVariable); // ReferenceError: undefinedVariable is not defined
}, 2000);

setTimeout(() => {
  if (typeof undefinedVariable !== 'undefined') {
    console.log(undefinedVariable);
  } else {
    console.log('undefinedVariable is not defined');
  }
}, 2000);