Pull latest overtype-hard changes into the github-playground.

Author: nedtwigg

browser-extension/src/playgrounds/github-playground.ts

@@ -1,10 +1,11 @@
+import hljs from "highlight.js";
 import OverType from "../overtype/overtype";
 
 export function githubPrNewCommentContentScript() {
     if (window.location.hostname !== "github.com") {
       return;
     }
-
+    OverType.setCodeHighlighter(hljsHighlighter);
     const ghCommentBox = document.getElementById(
       "new_comment_field"
     ) as HTMLTextAreaElement | null;
@@ -17,7 +18,7 @@ export function githubPrNewCommentContentScript() {
         padding: "var(--base-size-8)",
       });
     }
-  }
+}
 
 function modifyDOM(overtypeInput: HTMLTextAreaElement): HTMLElement {
   overtypeInput.classList.add("overtype-input");
@@ -31,3 +32,18 @@ function modifyDOM(overtypeInput: HTMLTextAreaElement): HTMLElement {
   overtypeContainer.classList.add("overtype-container");
   return overtypeContainer.parentElement!.closest("div")!;
 }
+
+function hljsHighlighter(code: string, language: string) {
+  try {
+    if (language && hljs.getLanguage(language)) {
+      const result = hljs.highlight(code, { language });
+      return result.value;
+    } else {
+      const result = hljs.highlightAuto(code);
+      return result.value;
+    }
+  } catch (error) {
+    console.warn("highlight.js highlighting failed:", error);
+    return code;
+  }
+}