diff --git a/lib/BWTC.js b/lib/BWTC.js
index 2b62f89..fbf9443 100644
--- a/lib/BWTC.js
+++ b/lib/BWTC.js
@@ -1,5 +1,6 @@
 /* A simple bzip-like BWT compressor with a range encoder; written as a
  * self-test of the BWT package. */
+// edited by ed.developer90@gmail.com
 if (typeof define !== 'function') { var define = require('amdefine')(module); }
 define(['./freeze','./BWT','./DefSumModel','./FenwickModel','./LogDistanceModel','./NoModel','./RangeCoder','./Stream','./Util'], function(freeze, BWT, DefSumModel, FenwickModel, LogDistanceModel, NoModel, RangeCoder, Stream, Util) {
     var EOF = Stream.EOF;
@@ -7,7 +8,7 @@ define(['./freeze','./BWT','./DefSumModel','./FenwickModel','./LogDistanceModel'
     var F_PROB_MAX  = 0xFF00;
     var F_PROB_INCR = 0x0100;
 
-    BWTC = Object.create(null);
+    var BWTC = Object.create(null);
     BWTC.MAGIC = "bwtc";
     BWTC.compressFile = Util.compressFileHelper(BWTC.MAGIC, function(input, output, size, props, finalByte) {
         var encoder = new RangeCoder(output);