Remove usage of map from array input

Author: blakeembrey

index.js

@@ -91,16 +91,17 @@ function pathtoRegexp (path, keys, options) {
     return attachKeys(path, keys);
   }
 
+  // Map array parts into regexps and return their source. We also pass
+  // the same keys and options instance into every generation to get
+  // consistent matching groups before we join the sources together.
   if (Array.isArray(path)) {
-    // Map array parts into regexps and return their source. We also pass
-    // the same keys and options instance into every generation to get
-    // consistent matching groups before we join the sources together.
-    path = path.map(function (value) {
-      return pathtoRegexp(value, keys, options).source;
-    });
+    var parts = [];
 
+    for (var i = 0; i < path.length; i++) {
+      parts.push(pathtoRegexp(path[i], keys, options).source);
+    }
     // Generate a new regexp instance by joining all the parts together.
-    return attachKeys(new RegExp('(?:' + path.join('|') + ')', flags), keys);
+    return attachKeys(new RegExp('(?:' + parts.join('|') + ')', flags), keys);
   }
 
   // Alter the path string into a usable regexp.