How to define Singleton in TypeScript

Question

What is the best and most convenient way to implement a Singleton pattern for a class in TypeScript? (Both with and without lazy initialisation).

Answer 1

I am surprised not to see the following pattern here, which actually looks very simple.

// shout.ts
class ShoutSingleton {
  helloWorld() { return 'hi'; }
}

export let Shout = new ShoutSingleton();

Usage

import { Shout } from './shout';
Shout.helloWorld();