// es6继承
class Point {
  x;
  y;
  constructor(x, y) {
    this.x = x;
    this.y = y;
  }
  print() {
    console.log(`Point:(${this.x},${this.y})`);
  }
}

class ColorPoint extends Point {
  color;
  constructor(x, y, color) {
    // 必须调用父类构造函数
    super(x, y);
    this.color = color;
  }

  // 覆盖父类方法
  print() {
    console.log(`ColorPoint:(${this.x},${this.y}) ${this.color}`);
  }
}

const p = new Point(1, 2);
p.print(); // Point:(1,2)

const cp = new ColorPoint(3, 4, "red");
cp.print(); // ColorPoint:(3,4) red

console.log(cp instanceof Point); // ture
console.log(cp instanceof ColorPoint); // ture
console.log(Point.prototype.isPrototypeOf(cp)); // ture
console.log(ColorPoint.prototype.isPrototypeOf(cp)); // ture