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

My solution for it:

export default class Modal {
    private static _instance : Modal = new Modal();

    constructor () {
        if (Modal._instance) 
            throw new Error("Use Modal.instance");
        Modal._instance = this;
    }

    static get instance () {
        return Modal._instance;
    }
}