Singleton Pattern

LoopbackApp.ts

class LoopbackApp {
  private static instance: Promise<any>;

  private constructor() {}

  public static get app(): Promise<any> {
    if (LoopbackApp.instance) return LoopbackApp.instance;

    LoopbackApp.instance = new Promise((resolve, reject) => {
      resolve();
    });

    return LoopbackApp.instance;
  }
}

async function plop() {
  const app = await LoopbackApp.app;
}