diff --git a/lib/index.cjs b/lib/index.cjs
index 64fcf0c..e6a6f46 100644
--- a/lib/index.cjs
+++ b/lib/index.cjs
@@ -82,22 +82,37 @@ function slug (value, maintainCase) {
 
 let slugger;
 
+let headings = [];
+
 function gfmHeadingId({ prefix = '' } = {}) {
   return {
     headerIds: false, // prevent deprecation warning; remove this once headerIds option is removed
     hooks: {
       preprocess(src) {
+        headings = [];
         slugger = new BananaSlug();
         return src;
       }
     },
     renderer: {
       heading(text, level, raw) {
-        raw = raw.toLowerCase().trim().replace(/<[!\/a-z].*?>/ig, '');
-        return `<h${level} id="${prefix}${slugger.slug(raw)}">${text}</h${level}>\n`;
+        raw = raw
+          .toLowerCase()
+          .trim()
+          .replace(/<[!\/a-z].*?>/gi, '');
+        const id = `${prefix}${slugger.slug(raw)}`;
+        const heading = { level, text, id };
+        headings.push(heading);
+
+        return `<h${level} id="${id}">${text}</h${level}>\n`;
       }
     }
   };
 }
 
+function getHeadingList() {
+  return headings;
+}
+
+exports.getHeadingList = getHeadingList;
 exports.gfmHeadingId = gfmHeadingId;
diff --git a/lib/index.umd.js b/lib/index.umd.js
index b09f4cb..af1f244 100644
--- a/lib/index.umd.js
+++ b/lib/index.umd.js
@@ -86,24 +86,39 @@
 
   let slugger;
 
+  let headings = [];
+
   function gfmHeadingId({ prefix = '' } = {}) {
     return {
       headerIds: false, // prevent deprecation warning; remove this once headerIds option is removed
       hooks: {
         preprocess(src) {
+          headings = [];
           slugger = new BananaSlug();
           return src;
         }
       },
       renderer: {
         heading(text, level, raw) {
-          raw = raw.toLowerCase().trim().replace(/<[!\/a-z].*?>/ig, '');
-          return `<h${level} id="${prefix}${slugger.slug(raw)}">${text}</h${level}>\n`;
+          raw = raw
+            .toLowerCase()
+            .trim()
+            .replace(/<[!\/a-z].*?>/gi, '');
+          const id = `${prefix}${slugger.slug(raw)}`;
+          const heading = { level, text, id };
+          headings.push(heading);
+
+          return `<h${level} id="${id}">${text}</h${level}>\n`;
         }
       }
     };
   }
 
+  function getHeadingList() {
+    return headings;
+  }
+
+  exports.getHeadingList = getHeadingList;
   exports.gfmHeadingId = gfmHeadingId;
 
 }));
diff --git a/spec/index.test.js b/spec/index.test.js
index 7312789..c469a37 100644
--- a/spec/index.test.js
+++ b/spec/index.test.js
@@ -1,5 +1,5 @@
 import { marked } from 'marked';
-import { gfmHeadingId } from '../src/index.js';
+import { getHeadingList, gfmHeadingId } from '../src/index.js';
 
 describe('marked-gfm-heading-id', () => {
   beforeEach(() => {
@@ -57,7 +57,16 @@ describe('marked-gfm-heading-id', () => {
   });
 
   test('weird headings', () => {
-    marked.use(gfmHeadingId());
+    let headings = [];
+    marked.use(gfmHeadingId(), {
+      hooks: {
+        postprocess(html) {
+          headings = getHeadingList();
+          return html;
+        }
+      }
+    });
+
     const markdown = `
 # foo 1
 
@@ -117,5 +126,27 @@ describe('marked-gfm-heading-id', () => {
 <h1 id="hello-world-1"><samp>Hello <ins>world!</ins></samp></h1>
 "
 `);
+
+    expect(headings.length).toBe(18);
+    expect(headings[0].id).toBe('foo-1');
+    expect(headings[1].id).toBe('foo');
+    expect(headings[2].id).toBe('foo-2');
+    expect(headings[3].id).toBe('html-in-header');
+    expect(headings[4].id).toBe('just-test');
+    expect(headings[5].id).toBe('just-test-2');
+
+    expect(headings[6].id).toBe('just--test-2-spaces-');
+    expect(headings[7].id).toBe('just-test-3');
+    expect(headings[8].id).toBe('just-test-4');
+    expect(headings[9].id).toBe('just-non-tags');
+    expect(headings[10].id).toBe('just-spaces');
+
+    expect(headings[11].id).toBe('just--weird-chars');
+    expect(headings[12].id).toBe('followed-by-weird-chars');
+    expect(headings[13].id).toBe('followed--space-then-weird-chars');
+    expect(headings[14].id).toBe('');
+    expect(headings[15].id).toBe('comment-');
+    expect(headings[16].id).toBe('hello-world');
+    expect(headings[17].id).toBe('hello-world-1');
   });
 });
diff --git a/src/index.d.ts b/src/index.d.ts
index 0feaa6b..4ea422a 100644
--- a/src/index.d.ts
+++ b/src/index.d.ts
@@ -1,4 +1,4 @@
-import type { MarkedExtension, marked } from "marked"
+import type {MarkedExtension, marked} from 'marked';
 
 /** Options for configuring marked-gfm-heading-id extension */
 interface GfmHeadingIdOptions {
@@ -10,6 +10,25 @@ interface GfmHeadingIdOptions {
  * Add `id` attribute to headings (h1, h2, h3, etc) like GitHub.
  *
  * @param options Options for the extension
- * @returns A {@link marked.MarkedExtension | MarkedExtension} to be passed to {@link marked.use | `marked.use()`}
+ * @returns A {@link marked.MarkedExtension | MarkedExtension} to be passed
+ *     to {@link marked.use | `marked.use()`}
  */
 export function gfmHeadingId(options?: GfmHeadingIdOptions): MarkedExtension;
+
+/**
+ * Headings information, can be used to create table of content
+ */
+export interface HeadingData {
+  level: number;
+  text: string;
+  id: string;
+}
+
+/**
+ * Returns a list of headings with the ids as computed by gfmHeadingId
+ *
+ * @param tokens a lexer output
+ * @param options Options for the extension
+ * @returns A string formatted the same as what would {@link gfmHeadingId} do.
+ */
+export function getHeadingList(): HeadingData[];
diff --git a/src/index.js b/src/index.js
index bce6dd2..aa6f12b 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,20 +1,34 @@
 import GithubSlugger from 'github-slugger';
 let slugger;
 
+let headings = [];
+
 export function gfmHeadingId({ prefix = '' } = {}) {
   return {
     headerIds: false, // prevent deprecation warning; remove this once headerIds option is removed
     hooks: {
       preprocess(src) {
+        headings = [];
         slugger = new GithubSlugger();
         return src;
       }
     },
     renderer: {
       heading(text, level, raw) {
-        raw = raw.toLowerCase().trim().replace(/<[!\/a-z].*?>/ig, '');
-        return `<h${level} id="${prefix}${slugger.slug(raw)}">${text}</h${level}>\n`;
+        raw = raw
+          .toLowerCase()
+          .trim()
+          .replace(/<[!\/a-z].*?>/gi, '');
+        const id = `${prefix}${slugger.slug(raw)}`;
+        const heading = { level, text, id };
+        headings.push(heading);
+
+        return `<h${level} id="${id}">${text}</h${level}>\n`;
       }
     }
   };
 }
+
+export function getHeadingList() {
+  return headings;
+}