diff --git a/hasher.js b/hasher.js
index b31a598..a038201 100644
--- a/hasher.js
+++ b/hasher.js
@@ -3,15 +3,15 @@ const crypto = require('crypto');
 function Hasher() {}
 
 Hasher.prototype.hashToIndex = function (key, modulo) {
+  key = key || 0;
   let ch;
   let hash = key;
-
   for (let i = 0; i < key.length; i++) {
     ch = key.charCodeAt(i);
     hash = ((hash << 5) - hash) + ch;
     hash = hash & hash;
   }
-  return Math.abs(hash || 0) % modulo;
+  return Math.abs(hash) % modulo;
 };
 
 Hasher.prototype.hashToHex = function (key, algorithm) {