move compose to main file

lib/utils.js

@@ -34,22 +34,6 @@ utils.last = function(arr, n) {
   return arr[arr.length - (n || 1)];
 };
 
-/**
- * Compose a matcher function with the given patterns
- */
-
-utils.compose = function(patterns, options, matcher) {
-  var fns = patterns.map(function(pattern) {
-    return matcher(pattern, options);
-  });
-
-  return function(file) {
-    var len = fns.length;
-    while (len--) if (fns[len](file)) return true;
-    return false;
-  };
-};
-
 /**
  * Get the `Snapdragon` instance to use
  */
@@ -220,6 +204,7 @@ utils.stripDrive = function(fp) {
  */
 
 utils.stripPrefix = function(str) {
+  if (!str || typeof str !== 'string') return str;
   if (str.charAt(0) !== '.') {
     return str;
   }