diff --git a/lib/parser.js b/lib/parser.js
index 451d022..7677c3f 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -381,30 +381,10 @@ function peg$parse(input, options) {
     return input.substring(peg$savedPos, peg$currPos);
   }
 
-  function offset() {
-    return peg$savedPos;
-  }
-
-  function range() {
-    return [peg$savedPos, peg$currPos];
-  }
-
   function location() {
     return peg$computeLocation(peg$savedPos, peg$currPos);
   }
 
-  function expected(description, location) {
-    location = location !== undefined
-      ? location
-      : peg$computeLocation(peg$savedPos, peg$currPos);
-
-    throw peg$buildStructuredError(
-      [peg$otherExpectation(description)],
-      input.substring(peg$savedPos, peg$currPos),
-      location
-    );
-  }
-
   function error(message, location) {
     location = location !== undefined
       ? location
diff --git a/src/pegjs.config.js b/src/pegjs.config.js
index d3750fd..ad69748 100644
--- a/src/pegjs.config.js
+++ b/src/pegjs.config.js
@@ -12,4 +12,12 @@ module.exports = {
 
     },
 
+    features: {
+
+        offset: false,
+        range: false,
+        expected: false,
+
+    },
+
 };