From 538db8ec575b0d61514e9eb57496c9034c79fbd3 Mon Sep 17 00:00:00 2001
From: Francis Lavoie <lavofr@gmail.com>
Date: Sat, 4 Apr 2020 19:19:25 -0400
Subject: [PATCH] Add JS to reset the toggle if the system theme changes when
 page closed

---
 src/resources/js/common.js | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/resources/js/common.js b/src/resources/js/common.js
index 995d20a..511c444 100644
--- a/src/resources/js/common.js
+++ b/src/resources/js/common.js
@@ -1,3 +1,21 @@
+// We want to run this as early as possible
+(function() {
+	// Grab the cached preferred color scheme
+	let cachedPref = localStorage.getItem('prefers-color-scheme');
+
+	// Grab the current preferred color scheme
+	let currentPref = window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
+
+	// If the preferred color scheme has changed since last page load
+	if (cachedPref !== currentPref) {
+		// We clear the toggle's value so it doesn't override the system choice
+		localStorage.removeItem('dark-mode-toggle');
+	}
+
+	// Set the preferred color scheme so it can be checked on a future page load
+	localStorage.setItem('prefers-color-scheme', currentPref);
+})();
+
 document.addEventListener('DOMContentLoaded', function() {
 	// Algolia search
 	docsearch({