use directories for structure

node_modules/is-valid-glob/index.js

@@ -0,0 +1,21 @@
+'use strict';
+
+module.exports = function isValidGlob(glob) {
+  if (typeof glob === 'string' && glob.length > 0) {
+    return true;
+  }
+  if (Array.isArray(glob)) {
+    return glob.length !== 0 && every(glob);
+  }
+  return false;
+};
+
+function every(arr) {
+  var len = arr.length;
+  while (len--) {
+    if (typeof arr[len] !== 'string' || arr[len].length <= 0) {
+      return false;
+    }
+  }
+  return true;
+}