singletontsyringe

How to implement singleton in Tsyringe


I am having trouble implementing singleton, because class marked as @singleton() is being recreated on every resolve().

Here is the example

// 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);

How can I get the desired behavior?


Solution

  • Singleton should be registered as follows

    container.register(
      "Foo",
      { useClass: Foo },
      { lifecycle: Lifecycle.Singleton } // <- this is important
    );