From cdcdc095df47c30d140d9d612390981d673141e9 Mon Sep 17 00:00:00 2001
From: MacDue <macdue@dueutil.tech>
Date: Mon, 18 Jul 2022 20:00:03 +0100
Subject: [PATCH] LibCore: Add Core::debounce(function, timeout)

This is a simple helper to debounce a function call, such as
an event handler. It avoids the function being called until
the event as settled down (i.e. after the timeout).
---
 Userland/Libraries/LibCore/Debounce.h | 29 +++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 Userland/Libraries/LibCore/Debounce.h

diff --git a/Userland/Libraries/LibCore/Debounce.h b/Userland/Libraries/LibCore/Debounce.h
new file mode 100644
index 0000000000..ba40a145bf
--- /dev/null
+++ b/Userland/Libraries/LibCore/Debounce.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibCore/Timer.h>
+
+namespace Core {
+
+template<typename TFunction>
+auto debounce(TFunction function, int timeout)
+{
+    RefPtr<Core::Timer> timer;
+    return [=]<typename... T>(T... args) mutable {
+        auto apply_function = [=] { function(args...); };
+        if (timer) {
+            timer->stop();
+            timer->on_timeout = move(apply_function);
+        } else {
+            timer = Core::Timer::create_single_shot(timeout, move(apply_function));
+        }
+        timer->start();
+    };
+};
+
+}