diff --git a/lib/system/has-flag.js b/lib/system/has-flag.js
index c9698f8..e70d7db 100644
--- a/lib/system/has-flag.js
+++ b/lib/system/has-flag.js
@@ -11,10 +11,10 @@ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLI
 */
 
 'use strict';
-module.exports = function(flag, argv) {
-	argv = argv || process.argv;
-	var prefix = flag.startsWith('-') ? '' : (flag.length === 1 ? '-' : '--');
-	var pos = argv.indexOf(prefix + flag);
+module.exports = function (flag, argv) {
 	var terminatorPos = argv.indexOf('--');
-	var pos !== -1 && (terminatorPos === -1 ? true : pos < terminatorPos);
+ 	var prefix = /^-{1,2}/.test(flag) ? '' : '--';
+	var pos = argv.indexOf(prefix + flag);
+
+	return pos !== -1 && (terminatorPos === -1 ? true : pos < terminatorPos);
 };