diff --git a/lib/buf.js b/lib/buf.js
index 8625849..55f39c8 100644
--- a/lib/buf.js
+++ b/lib/buf.js
@@ -7,7 +7,7 @@ class InputBuffer {
     }
 
     _replace() {
-        if (this._buf.indexOf(BACK_SLASH) < 0) {
+        if (!this._buf.includes(BACK_SLASH)) {
             return;
         }
         let len = this._buf.length;