● 这篇文章和大家一起学习创建类来管理我们的锻炼数据
● 首先我们先创建这些类，然后讲锻炼数据中的数据写出来

class Workout {
  date = new Date();

  constructor(coords, distance, duration) {
    this.coords = coords;
    this.distance = distance; //km
    this.duration = duration; //min
  }
}

● 通过ID来生成唯一标识符

class Workout {
  date = new Date();
  id = (new Date() + '').slice(-10); //通过取时间戳的方式来当作唯一标识符

  constructor(coords, distance, duration) {
    this.coords = coords;
    this.distance = distance; //km
    this.duration = duration; //min
  }
}

● 之后我们通过继承的方式来生成跑步和骑行的类

class Running extends Workout {
  constructor(coords, distance, duration, cadence) {
    super(coords, distance, duration); //调用父类构造函数
    this.cadence = cadence;
  }
}

class Cycling extends Workout {
  constructor(coords, distance, duration, elevationGain) {
    super(coords, distance, duration);
    this.elevationGain = elevationGain;
  }
}

● 但是对于跑步和骑行来说，还有其他的方法参数，比如速度，

class Running extends Workout {
  constructor(coords, distance, duration, cadence) {
    super(coords, distance, duration); //调用父类构造函数
    this.cadence = cadence;
    this.calcPace();
  }
  //计算配速
  calcPace() {
    this.pace = this.duration / this.distance;
    return this.pace;
  }
}

class Cycling extends Workout {
  constructor(coords, distance, duration, elevationGain) {
    super(coords, distance, duration);
    this.elevationGain = elevationGain;
    this.calcSpeed();
  }
  //计算速度
  calcSpeed() {
    this.speed = this.distance / (this.duration / 60);
    return this.speed;
  }
}

● 之后我们创建一些实例来测试一下我们的类有没有问题

const run1 = new Running([39, -12], 5.2, 24, 178);
const cycling1 = new Cycling([39, -12], 27, 95, 523);
console.log(run1, cycling1);

● 很明显，我们的id唯一标识符是有问题的，我们来修改一下

class Workout {
  date = new Date();
  id = (Date.now() + '').slice(-10);

  constructor(coords, distance, duration) {
    this.coords = coords;
    this.distance = distance; //km
    this.duration = duration; //min
  }
}

class Running extends Workout {
  //继承Workout类
  constructor(coords, distance, duration, cadence) {
    super(coords, distance, duration); //调用父类构造函数
    this.cadence = cadence;
    this.calcPace();
  }
  //计算配速
  calcPace() {
    this.pace = this.duration / this.distance;
    return this.pace;
  }
}

当然，这种方式创建ID，仍然可能出现相同的id，但是我们暂且先这么做，自己有兴趣的话可以通过UUID的方式在后面增加，这种碰撞率就非常低了