如何在Class属性中设置条件？

Question

我要设置

private numberOfWheels：数字； //大于-1

如何在班级内部设置？

class Vehicle {
  private numberOfWheels: number; // bigger than -1
  public wheels: Wheel[];
  private fuel: number;

  constructor(numberOfWheels: number, wheels: Wheel[], fuel: number) {
    this.numberOfWheels = numberOfWheels
    this.wheels = wheels;
    this.fuel = fuel;
  }
  getNumberOfWheels(): number { return this.numberOfWheels; }

  getFuel(): number {return this.fuel; }
}