From 209f9b583bb954843cbfa7b62c2c558a4927dbe9 Mon Sep 17 00:00:00 2001
From: littensy <56808540+littensy@users.noreply.github.com>
Date: Sat, 3 May 2025 21:17:03 -0700
Subject: [PATCH] fix: check previous value before calling listener

---
 packages/charm/src/listen.luau    | 8 ++++++++
 packages/charm/src/subscribe.luau | 8 ++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/packages/charm/src/listen.luau b/packages/charm/src/listen.luau
index 56c3deb..9de1d9c 100644
--- a/packages/charm/src/listen.luau
+++ b/packages/charm/src/listen.luau
@@ -8,6 +8,7 @@ local resumeTracking = signals.resumeTracking
 
 local function listen<T>(selector: () -> T, listener: (state: T, previous: T?, dispose: () -> ()) -> ()): () -> ()
 	local disposed = false
+	local mounted = true
 	local current: T?
 	local dispose: () -> ()
 
@@ -21,6 +22,13 @@ local function listen<T>(selector: () -> T, listener: (state: T, previous: T?, d
 	dispose = effectScope(function()
 		effect(function()
 			local value = selector()
+
+			if mounted then
+				mounted = false
+			elseif value == current then
+				return
+			end
+
 			local previous = current
 			current = value
 
diff --git a/packages/charm/src/subscribe.luau b/packages/charm/src/subscribe.luau
index 9797d55..9d9e1e6 100644
--- a/packages/charm/src/subscribe.luau
+++ b/packages/charm/src/subscribe.luau
@@ -8,17 +8,17 @@ local resumeTracking = signals.resumeTracking
 
 local function subscribe<T>(selector: () -> T, listener: (T, T) -> ()): () -> ()
 	local current: T
-	local mount = true
+	local mounted = true
 	local dispose: () -> ()
 
 	dispose = effectScope(function()
 		effect(function()
 			local value = selector()
 
-			if mount then
+			if mounted then
 				current = value
-				mount = false
-			else
+				mounted = false
+			elseif value ~= current then
 				local previous = current
 				current = value