getOrSetCache

function getOrSetCache (key, functionObject) {
	var item = sessionStorage.getItem(key);
	if (item) {
		var objItem = JSON.parse(item);
		return objItem;
	}

	var result = functionObject();
	var stringifyResult = JSON.stringify(result);
	sessionStorage.setItem(key, stringifyResult);
	return result;
}