Singleton pattern with JS Module

main.js

import Singleton from './Singleton';

const config = Singleton.getInstance();
console.log(config.isShowHeader);  // true

Singleton.js

class Singleton {
	constructor() {
		this.init();
	}
    init() {
        // fetch values
        this._showHeader = true;
        this._pattern = 101;
    }
	get isShowHeader() {
		return this._showHeader;
	}
    get pattern() {
        return this._pattern;
    }
}

const instance = new Singleton();
function getInstance(val) {
	return instance;
}

export default { getInstance };