wp-calypso/desktop/app/lib/app-quit/index.js

/**
 * Module variables
 */
let quitter = false;

function AppQuit() {
	this.canQuit = false;
}

AppQuit.prototype.shouldQuitToBackground = function () {
	if ( this.canQuit ) {
		this.canQuit = false;
		return false;
	}

	return true;
};

AppQuit.prototype.allowQuit = function () {
	this.canQuit = true;
};

if ( ! quitter ) {
	quitter = new AppQuit();
}

module.exports = quitter;