check collection name to be no empty string before running function o…

…n it for pluralize

lib/utils.js

@@ -53,6 +53,12 @@ exports.toCollectionName = function(name, pluralize) {
     return name;
   }
   if (typeof pluralize === 'function') {
+    if (typeof name !== 'string') {
+      throw new TypeError('Collection name must be a string');
+    }
+    if (name.length === 0) {
+      throw new TypeError('Collection name cannot be empty');
+    }
     return pluralize(name);
   }
   return name;