public registerSingleton()

in src/dependency-container.ts [162:210]

46 lines of code
6 McCabe index (conditional complexity)


  public registerSingleton<T>(
    from: InjectionToken<T>,
    to: InjectionToken<T>
  ): InternalDependencyContainer;
  public registerSingleton<T>(
    token: constructor<T>,
    to?: constructor<any>
  ): InternalDependencyContainer;
  public registerSingleton<T>(
    from: InjectionToken<T>,
    to?: InjectionToken<T>
  ): InternalDependencyContainer {
    if (isNormalToken(from)) {
      if (isNormalToken(to)) {
        return this.register(
          from,
          {
            useToken: to
          },
          {lifecycle: Lifecycle.Singleton}
        );
      } else if (to) {
        return this.register(
          from,
          {
            useClass: to
          },
          {lifecycle: Lifecycle.Singleton}
        );
      }

      throw new Error(
        'Cannot register a type name as a singleton without a "to" token'
      );
    }

    let useClass = from;
    if (to && !isNormalToken(to)) {
      useClass = to;
    }

    return this.register(
      from,
      {
        useClass
      },
      {lifecycle: Lifecycle.Singleton}
    );
  }