问题描述
我在实现单例时遇到问题,因为标记为 @singleton() 的类在每个 resolve() 上都被重新创建。
这是例子
// Foo.ts This is singleton and and must be created only once
import { injectable,singleton } from "tsyringe";
@injectable()
@singleton()
export class Foo {
constructor() {
console.log("Constractor of Foo");
}
}
// Bar.ts this is Bar and should be created every time. It uses the singleton
import { inject,injectable,Lifecycle,scoped } from "tsyringe";
import { Foo } from "./Foo";
@injectable()
export class Bar {
constructor(@inject("Foo") private foo: Foo) {
console.log("Constractor of Bar");
}
}
// main.ts this is resolving Bar two times.
// expected output:
// Constractor of Foo
// Constractor of Bar
// Constractor of Bar
// Actual output:
// Constractor of Foo
// Constractor of Bar
// Constractor of Foo
// Constractor of Bar
import "reflect-Metadata";
import { container } from "tsyringe";
import { Bar } from "./Bar";
import { Foo } from "./Foo";
container.register("Foo",{ useClass: Foo });
container.register("Bar",{ useClass: Bar });
const instance = container.resolve(Bar);
const instance1 = container.resolve(Bar);
如何获得所需的行为?
解决方法
单例应该如下注册
container.register(
"Foo",{ useClass: Foo },{ lifecycle: Lifecycle.Singleton } // <- this is important
);
,
我认为你让你的生活变得更加困难。我发现您所做的事情和您提出的解决方案存在一些问题。这是 @singleton()
装饰器的 source code:
function singleton<T>(): (target: constructor<T>) => void {
return function(target: constructor<T>): void {
injectable()(target);
globalContainer.registerSingleton(target);
};
}
- 首先,你不需要用
@injectable()
装饰,因为 tsyringe 已经用@singleton()
添加了。 - 最后,如果您只是不注册
Foo
和Bar
,它们将自动注册为单例(当然,{ lifecycle: Lifecycle.Singleton }
选项已经设置)在 {{1 }} 函数。