用TS声明一个二维向量

可以使用以下代码声明一个二维向量：

class Vector2D {
  constructor(public x: number, public y: number) {}

  add(other: Vector2D): Vector2D {
    return new Vector2D(this.x + other.x, this.y + other.y);
  }

  subtract(other: Vector2D): Vector2D {
    return new Vector2D(this.x - other.x, this.y - other.y);
  }

  multiply(scalar: number): Vector2D {
    return new Vector2D(this.x * scalar, this.y * scalar);
  }

  divide(scalar: number): Vector2D {
    return new Vector2D(this.x / scalar, this.y / scalar);
  }

  get length(): number {
    return Math.sqrt(this.x * this.x + this.y * this.y);
  }

  normalize(): Vector2D {
    const length = this.length;
    return new Vector2D(this.x / length, this.y / length);
  }
}

const v1 = new Vector2D(1, 2);
const v2 = new Vector2D(3, 4);

console.log(v1.add(v2)); // Vector2D { x: 4, y: 6 }
console.log(v1.subtract(v2)); // Vector2D { x: -2, y: -2 }
console.log(v1.multiply(2)); // Vector2D { x: 2, y: 4 }
console.log(v1.divide(2)); // Vector2D { x: 0.5, y: 1 }
console.log(v1.length); // 2.23606797749979
console.log(v1.normalize()); // Vector2D { x: 0.4472135954999579, y: 0.8944271909999159 }