Merge pull request #4149 from fred-bf/feat/auto-detach-scrolling

feat: auto detach scrolling

app/components/chat.tsx

@@ -6,6 +6,7 @@ import React, {
   useMemo,
   useCallback,
   Fragment,
+  RefObject,
 } from "react";
 
 import SendWhiteIcon from "../icons/send-white.svg";
@@ -382,11 +383,13 @@ function ChatAction(props: {
   );
 }
 
-function useScrollToBottom() {
+function useScrollToBottom(
+  scrollRef: RefObject<HTMLDivElement>,
+  detach: boolean = false,
+) {
   // for auto-scroll
-  const scrollRef = useRef<HTMLDivElement>(null);
-  const [autoScroll, setAutoScroll] = useState(true);
 
+  const [autoScroll, setAutoScroll] = useState(true);
   function scrollDomToBottom() {
     const dom = scrollRef.current;
     if (dom) {
@@ -399,7 +402,7 @@ function useScrollToBottom() {
 
   // auto scroll
   useEffect(() => {
-    if (autoScroll) {
+    if (autoScroll && !detach) {
       scrollDomToBottom();
     }
   });
@@ -658,7 +661,17 @@ function _Chat() {
   const [userInput, setUserInput] = useState("");
   const [isLoading, setIsLoading] = useState(false);
   const { submitKey, shouldSubmit } = useSubmitHandler();
-  const { scrollRef, setAutoScroll, scrollDomToBottom } = useScrollToBottom();
+  const scrollRef = useRef<HTMLDivElement>(null);
+  const isScrolledToBottom = scrollRef?.current
+    ? Math.abs(
+        scrollRef.current.scrollHeight -
+          (scrollRef.current.scrollTop + scrollRef.current.clientHeight),
+      ) <= 1
+    : false;
+  const { setAutoScroll, scrollDomToBottom } = useScrollToBottom(
+    scrollRef,
+    isScrolledToBottom,
+  );
   const [hitBottom, setHitBottom] = useState(true);
   const isMobileScreen = useMobileScreen();
   const navigate = useNavigate();
@@ -1003,7 +1016,6 @@ function _Chat() {
     setHitBottom(isHitBottom);
     setAutoScroll(isHitBottom);
   };
-
   function scrollToBottom() {
     setMsgRenderIndex(renderMessages.length - CHAT_PAGE_SIZE);
     scrollDomToBottom();