TypeScript 使用实例访问静态变量
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TypeScript Access Static Variables Using Instances
提问by Nigh7Sh4de
So in most OOP languages static variables can also be called classvariables, ie their value is sharedamong all instances of this class. For example, in my game I have a class Bulletwhich is extended by GreenBulletand PinkBullet. I want these subclasses to have a "class" or "static" variable called ammoso that I can keep track of the ammo count for that specific ammo type. But here is the catch: I want to be able to access this property through an instance of the subclass.
所以在大多数 OOP 语言中，静态变量也可以称为类变量，即它们的值在此类的所有实例之间共享。例如，在我的游戏中，我有一个Bullet由GreenBullet和扩展的类PinkBullet。我希望这些子类有一个名为“类”或“静态”的变量，ammo以便我可以跟踪该特定弹药类型的弹药计数。但这里有一个问题：我希望能够通过子类的实例访问这个属性。
Example:
例子：
var bullet: GreenBullet = new GreenBullet()
if (bullet.ammo <= 0)
return;
bullet.shoot();
bullet.ammo --;
I want ALL instances of GreenBulletto be aware of this change to their ammo count.
我希望所有实例都GreenBullet意识到他们弹药数量的变化。
回答by zlumer
First option is to create instance accessors to static variable:
第一个选项是创建静态变量的实例访问器：
class GreenBullet
{
static ammo: number = 0;
get ammo(): number { return GreenBullet.ammo; }
set ammo(val: number) { GreenBullet.ammo = val; }
}
var b1 = new GreenBullet();
b1.ammo = 50;
var b2 = new GreenBullet();
console.log(b2.ammo); // 50
If you want all subclasses of Bullet(including itself) to have separate ammo count, you can make it that way:
如果您希望Bullet（包括其自身）的所有子类都具有单独的弹药计数，您可以这样做：
class Bullet
{
static ammo: number = 0;
get ammo(): number { return this.constructor["ammo"]; }
set ammo(val: number) { this.constructor["ammo"] = val; }
}
class GreenBullet extends Bullet { }
class PinkBullet extends Bullet { }
var b1 = new GreenBullet();
b1.ammo = 50;
var b2 = new GreenBullet();
console.log(b2.ammo); // 50
var b3 = new PinkBullet();
console.log(b3.ammo); // 0
On a side note, I'm fairly sure you should not store bullet count in a static variable.
附带说明一下，我很确定您不应该将子弹数存储在静态变量中。
