From 256cc9592a3f31fc392e1ccdb699aa206b7b47ce Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Sat, 26 Aug 2023 23:49:28 +0800
Subject: ...

---
 FrontEnd/src/components/hooks/useScrollToBottom.ts | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 FrontEnd/src/components/hooks/useScrollToBottom.ts

(limited to 'FrontEnd/src/components/hooks/useScrollToBottom.ts')

diff --git a/FrontEnd/src/components/hooks/useScrollToBottom.ts b/FrontEnd/src/components/hooks/useScrollToBottom.ts
new file mode 100644
index 00000000..79fcda16
--- /dev/null
+++ b/FrontEnd/src/components/hooks/useScrollToBottom.ts
@@ -0,0 +1,44 @@
+import { useRef, useEffect } from "react";
+import { fromEvent, filter, throttleTime } from "rxjs";
+
+function useScrollToBottom(
+  handler: () => void,
+  enable = true,
+  option = {
+    maxOffset: 5,
+    throttle: 1000,
+  },
+): void {
+  const handlerRef = useRef<(() => void) | null>(null);
+
+  useEffect(() => {
+    handlerRef.current = handler;
+
+    return () => {
+      handlerRef.current = null;
+    };
+  }, [handler]);
+
+  useEffect(() => {
+    const subscription = fromEvent(window, "scroll")
+      .pipe(
+        filter(
+          () =>
+            window.scrollY >=
+            document.body.scrollHeight - window.innerHeight - option.maxOffset,
+        ),
+        throttleTime(option.throttle),
+      )
+      .subscribe(() => {
+        if (enable) {
+          handlerRef.current?.();
+        }
+      });
+
+    return () => {
+      subscription.unsubscribe();
+    };
+  }, [enable, option.maxOffset, option.throttle]);
+}
+
+export default useScrollToBottom;
-- 
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