diff --git a/protocol/src/main/resources/javascript/buffer/ByteBuffer.js b/protocol/src/main/resources/javascript/buffer/ByteBuffer.js
index e555f967..834344ce 100644
--- a/protocol/src/main/resources/javascript/buffer/ByteBuffer.js
+++ b/protocol/src/main/resources/javascript/buffer/ByteBuffer.js
@@ -326,7 +326,7 @@ const ByteBuffer = function() {
                 }
             }
         }
-        return readInt64(new Uint8Array(buffer.slice(0, count)));
+        return readInt64(new Uint8Array(buffer.slice(0, count))).toNumber();
     };
 
     this.writeFloat = function(value) {
diff --git a/protocol/src/test/javascript/zfoojs/buffer/ByteBuffer.js b/protocol/src/test/javascript/zfoojs/buffer/ByteBuffer.js
index f132782e..bcc684d6 100644
--- a/protocol/src/test/javascript/zfoojs/buffer/ByteBuffer.js
+++ b/protocol/src/test/javascript/zfoojs/buffer/ByteBuffer.js
@@ -322,7 +322,7 @@ const ByteBuffer = function() {
                 }
             }
         }
-        return readInt64(new Uint8Array(buffer.slice(0, count)));
+        return readInt64(new Uint8Array(buffer.slice(0, count))).toNumber();
     };
 
     this.writeFloat = function(value) {