标签绑定
当我们把两个或者多个具体实现绑定到同一个抽象时,可以使用标签绑定来修复 模糊匹配
错误。
注意 Ninja
类的构造器参数是如何被 @tagged
装饰器标记的:
interface Weapon {}
@injectable()
class Katana implements Weapon {}
@injectable()
class Shuriken implements Weapon {}
interface Ninja {
katana: Weapon;
shuriken: Weapon;
}
@injectable()
class Ninja implements Ninja {
public katana: Weapon;
public shuriken: Weapon;
public constructor(
@inject("Weapon") @tagged("canThrow", false) katana: Weapon,
@inject("Weapon") @tagged("canThrow", true) shuriken: Weapon
) {
this.katana = katana;
this.shuriken = shuriken;
}
}
我们将 Katana
和 Shuriken
绑定到了 Weapob
,但是 whenTargetTagged
限制避免了 模糊匹配
的错误:
container.bind<Ninja>(ninjaId).to(Ninja);
container.bind<Weapon>(weaponId).to(Katana).whenTargetTagged("canThrow", false);
container.bind<Weapon>(weaponId).to(Shuriken).whenTargetTagged("canThrow", true);