diff --git a/dist/jszip.js b/dist/jszip.js
index 9f0ffc1d..aaca594e 100644
--- a/dist/jszip.js
+++ b/dist/jszip.js
@@ -1855,7 +1855,7 @@ DataReader.prototype = {
             i;
         this.checkOffset(size);
         for (i = this.index + size - 1; i >= this.index; i--) {
-            result = (result << 8) + this.byteAt(i);
+            result = (result * 256) + this.byteAt(i);
         }
         this.index += size;
         return result;
@@ -11367,4 +11367,4 @@ module.exports = typeof setImmediate === 'function' ? setImmediate :
 	};
 
 },{}]},{},[10])(10)
-});
\ No newline at end of file
+});
diff --git a/lib/reader/DataReader.js b/lib/reader/DataReader.js
index c4e1e03b..5dae5e57 100644
--- a/lib/reader/DataReader.js
+++ b/lib/reader/DataReader.js
@@ -61,7 +61,7 @@ DataReader.prototype = {
             i;
         this.checkOffset(size);
         for (i = this.index + size - 1; i >= this.index; i--) {
-            result = (result << 8) + this.byteAt(i);
+            result = (result * 256) + this.byteAt(i);
         }
         this.index += size;
         return result;