public static function currency( $value, $decimals = 2, $currencyCode = null )
	{
		$app = Application::instance();
		$currencyCode = $currencyCode ?: $app->getConfig('app.settings.currency');

		$nf = new \NumberFormatter(\Locale::getDefault(), \NumberFormatter::CURRENCY);
		$nf->setAttribute(\NumberFormatter::MAX_FRACTION_DIGITS, $decimals);
		return $nf->formatCurrency($value, $currencyCode);
	}