From 8266ebf3c61c9c6a4aa98cbddd64814230b83d7d Mon Sep 17 00:00:00 2001
From: MacDue <macdue@dueutil.tech>
Date: Mon, 18 Jul 2022 20:03:11 +0100
Subject: [PATCH] TextEditor: Debounce update_preview() in on_change event

This avoids lag spikes when undoing/redoing large chunks of HTML/CSS
with the HTML preview open. This had been bugging me when reducing
LibWeb issues in the text editor. The debounce timeout is 100ms
so the delay should not be noticeable.
---
 Userland/Applications/TextEditor/MainWidget.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Userland/Applications/TextEditor/MainWidget.cpp b/Userland/Applications/TextEditor/MainWidget.cpp
index 13d1eaf2e6..94b128d74f 100644
--- a/Userland/Applications/TextEditor/MainWidget.cpp
+++ b/Userland/Applications/TextEditor/MainWidget.cpp
@@ -11,6 +11,7 @@
 #include <AK/URL.h>
 #include <Applications/TextEditor/TextEditorWindowGML.h>
 #include <LibConfig/Client.h>
+#include <LibCore/Debounce.h>
 #include <LibCore/File.h>
 #include <LibCpp/SyntaxHighlighter.h>
 #include <LibDesktop/Launcher.h>
@@ -63,9 +64,10 @@ MainWidget::MainWidget()
     else
         VERIFY_NOT_REACHED();
 
-    m_editor->on_change = [this] {
+    m_editor->on_change = Core::debounce([this] {
         update_preview();
-    };
+    },
+        100);
 
     m_editor->on_modified_change = [this](bool modified) {
         window()->set_modified(modified);