Implement replies in post header

web/static/thread.js

@@ -0,0 +1,34 @@
+const posts = Array.from(document.querySelectorAll("article"));
+
+const replies = {};
+
+for (const post of posts) {
+    const postId = +post.id.split("-")[1];
+    const postBody = post.querySelector("p").textContent;
+
+    const replyLinkIds = [...postBody.matchAll(/(?:^|\s)>>(\d+)\b/g)].map(m => parseInt(m[1]));
+    for (const replyLinkId of replyLinkIds) {
+        replies[replyLinkId] = replies[replyLinkId] ?
+            replies[replyLinkId].add(postId) :
+            replies[replyLinkId] = new Set([postId]);
+    }
+}
+
+for (const postId in replies) {
+    const post = $(`post-${postId}`);
+    const postRepliesContainer = post.querySelector(".post-replies");
+
+    const replyIds = Array.from(replies[postId]);
+    for (const replyId of replyIds) {
+        const replyLink = document.createElement("a");
+        replyLink.textContent = `>>${replyId}`;
+        replyLink.classList.add("reply-link-header");
+        replyLink.setAttribute("href", `#post-${replyId}`);
+
+        replyLink.onmouseover = (e) => highlightPost(+replyId, e);
+        replyLink.onmouseleave = (e) => highlightPost(+replyId, e, false);
+        replyLink.onclick = onReplyLinkClick;
+
+        postRepliesContainer.append(replyLink);
+    }
+}