diff --git a/markdown-it-attrs.browser.js b/markdown-it-attrs.browser.js
index 93cb7fd..5e2db6a 100644
--- a/markdown-it-attrs.browser.js
+++ b/markdown-it-attrs.browser.js
@@ -69,6 +69,12 @@ function test(tokens, i, t) {
 
   };
   var ii = t.shift !== undefined ? i + t.shift : t.position;
+
+  if (t.shift !== undefined && ii < 0) {
+    // we should never shift to negative indexes (rolling around to back of array)
+    return res;
+  }
+
   var token = get(tokens, ii); // supports negative ii
 
   if (token === undefined) {
diff --git a/package-lock.json b/package-lock.json
index adfc1c3..c5f978b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "markdown-it-attrs",
-  "version": "4.1.2",
+  "version": "4.1.3",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "markdown-it-attrs",
-      "version": "4.1.2",
+      "version": "4.1.3",
       "license": "MIT",
       "devDependencies": {
         "@babel/core": "^7.15.5",
diff --git a/package.json b/package.json
index 6bafd24..d3ce6ee 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "markdown-it-attrs",
-  "version": "4.1.2",
+  "version": "4.1.3",
   "description": "Add classes, identifiers and attributes to your markdown with {} curly brackets, similar to pandoc's header attributes",
   "main": "index.js",
   "license": "MIT",