tsyringeの@Injectableの挙動

tsyringe.ts

import "reflect-metadata"
import { container, inject, injectable } from "tsyringe"

@injectable()
class A {
  constructor() {
    console.log("class A instantiated!")
  }
}

@injectable()
class B {
  constructor(
    @inject(A)
    private a: A
  ) {
    console.log("class B instantiated!")
  }
}

container.resolve(A)
container.resolve(B)
// console.log outputs
//  class A instantiated!
//  class A instantiated!
//  class B instantiated!

with-singleton.ts

import "reflect-metadata"
import { container, inject, injectable, singleton } from "tsyringe"

@injectable()
class A {
  constructor() {
    console.log("class A instantiated!")
  }
}

@singleton()
class C {
  constructor() {
    console.log("class C instantiated!")
  }
}

@injectable()
class B {
  constructor(
    @inject(A)
    private a: A,
    @inject(C)
    private c: C
  ) {
    console.log("class B instantiated!")
  }
}



container.resolve(A)
container.resolve(C)
container.resolve(B)
// console.log outputs
//  class A instantiated!
//  class C instantiated!
//  class A instantiated!
//  class B instantiated!