1 files changed, 49 insertions, 0 deletions
diff --git a/FrontEnd/src/app/utilities/useScrollToTop.ts b/FrontEnd/src/app/utilities/useScrollToTop.ts
new file mode 100644
index 00000000..da63cb0a
--- /dev/null
+++ b/FrontEnd/src/app/utilities/useScrollToTop.ts
@@ -0,0 +1,49 @@
+import React from "react";
+import { fromEvent } from "rxjs";
+import { filter, throttleTime, tap } from "rxjs/operators";
+
+function useScrollToTop(
+  handler: () => void,
+  enable = true,
+  option = {
+    maxOffset: 50,
+    throttle: 1000,
+  }
+): void {
+  const handlerRef = React.useRef<(() => void) | null>(null);
+
+  React.useEffect(() => {
+    handlerRef.current = handler;
+
+    return () => {
+      handlerRef.current = null;
+    };
+  }, [handler]);
+
+  React.useEffect(() => {
+    const subscription = fromEvent(window, "scroll")
+      .pipe(
+        tap(() => {
+          console.log(
+            `Scroll event fired: ${window.scrollY}, time: ${Date.now()}.`
+          );
+        }),
+        filter(() => {
+          return window.scrollY <= option.maxOffset;
+        }),
+        throttleTime(option.throttle)
+      )
+      .subscribe(() => {
+        if (enable) {
+          console.log(`Fire scroll to top event, time: ${Date.now()}.`);
+          handlerRef.current?.();
+        }
+      });
+
+    return () => {
+      subscription.unsubscribe();
+    };
+  }, [enable, option.maxOffset, option.throttle]);
+}
+
+export default useScrollToTop;