Add ID to headings

src/index.ts

@@ -2,6 +2,7 @@ import capitalize from "lodash.capitalize"
 import { visit } from "unist-util-visit"
 import { toHast } from "mdast-util-to-hast"
 import { toHtml } from "hast-util-to-html"
+import { toString } from 'mdast-util-to-string';
 import { FindAndReplaceList, findAndReplace as mdastFindReplace } from "mdast-util-find-and-replace"
 
 // !?               -> optional embedding
@@ -320,5 +321,13 @@ export default function ofm() {
                 }
             }
         })
+
+        visit(tree, "heading", (node) => {
+            node.data = {
+                hProperties: {
+                    id: toString(node)
+                }
+            };
+        });
     }
 }