Example 3-2. Conditional async step

var user = {
	authenticated: false,
	login: function () {
		// Returns a promise for the login request
		// Set authenticated to true and fulfill promise when login succeeds
	}
};

// Avoid this style of conditional async execution
function showMainMenu() {
	if (!user.authenticated) {
		user.login().then(showMainMenu);
		return;
	}
	// ... Code to display main menu
}