init

lib/hooks/use-follow-scroll.ts

@@ -0,0 +1,43 @@
+import { useEffect, useRef } from "react";
+
+const scrollToEnd = () => {
+  window.scrollTo({
+    top: document.body.scrollHeight,
+    left: 0,
+  });
+};
+
+export function useFollowScroll(shouldFollow: boolean) {
+  const shouldFollowRef = useRef(shouldFollow);
+  const scrollRef = useRef(false);
+  const triggeredBySelfRef = useRef(false);
+
+  useEffect(() => {
+    const handleScroll = () => {
+      if (triggeredBySelfRef.current) {
+        triggeredBySelfRef.current = false;
+        return;
+      }
+      scrollRef.current = true;
+    };
+    window.addEventListener("scroll", handleScroll);
+    return () => window.removeEventListener("scroll", handleScroll);
+  }, []);
+
+  useEffect(() => {
+    if (!scrollRef.current && shouldFollowRef.current) {
+      setTimeout(() => {
+        triggeredBySelfRef.current = true;
+        scrollToEnd();
+      });
+    }
+  });
+
+  useEffect(() => {
+    shouldFollowRef.current = shouldFollow;
+    if (!shouldFollow) {
+      // Reset scrollRef
+      scrollRef.current = false;
+    }
+  }, [shouldFollow]);
+}