diff --git a/apps/web/src/lib/incrementalHighlighting.ts b/apps/web/src/lib/incrementalHighlighting.ts
index fef3598a21520c9386b093ac512029876c74e38c..4124d858f159c6513e63a98d4c42dfbd46cc12e6 100644
--- a/apps/web/src/lib/incrementalHighlighting.ts
+++ b/apps/web/src/lib/incrementalHighlighting.ts
@@ -18,7 +18,7 @@ export function createIncrementalHighlightedDocument(
   highlighter: DiffsHighlighter,
   language: string,
   theme: DiffThemeName,
-) {
+): (code: string) => ReturnType<DiffsHighlighter["codeToHast"]> {
   const options = { lang: language, theme };
   const newline = { type: "text" as const, value: "\n" };
   let cached: