duration = function duration() {
	for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
		args[_key] = arguments[_key];
	}

	// if is countdown x amount of milliseconds
	if (typeof args[0] === 'number' && typeof args[1] === 'string') {
		if (!TimeUnit[args[1]]) {
			throw '"' + args[1] + '" is not a valid amount.';
		}
		return args[0] * TimeUnit[args[1]];
	}

	// is date diff
	if (isDate(args[0])) {
		return dateDiff.apply(undefined, args);
	}

	// is duration in milliseconds
	if (typeof args[0] === 'number' && Array.isArray(args[1])) {
		return timeDuration.apply(undefined, args);
	}

	return null;
}
Tick.helper.duration(10, 'seconds') -> milliseconds
Tick.helper.duration(a, b, format, cascade) -> [0, 10, 20, 4, 0];
@param args
@returns {*}