refactor: embrace scope cleanup, restructure code

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
         run: sh bin/check.sh
 
       - name: Run tests
-        run: sh bin/test.sh
+        run: lute tests/init.luau
 
       - name: Build models
         run: sh bin/build.sh

.gitignore

@@ -1,7 +1,7 @@
 /.vscode
 /build
 /roblox_packages
-/packages/**/wally.lock
+/pkgs/**/wally.lock
 /sourcemap.json
 *.tsbuildinfo
 *.rbxm

.luaurc

@@ -2,5 +2,9 @@
 	"languageMode": "strict",
 	"lint": {
 		"LocalShadow": false
+	},
+	"aliases": {
+		"tests": "tests",
+		"pkgs": "packages"
 	}
 }

bin/build.sh

@@ -1,5 +1,5 @@
 mkdir build
-rojo build packages/charm -o build/charm.rbxm
-rojo build packages/charm-sync -o build/charm-sync.rbxm
-rojo build packages/react-charm -o build/react-charm.rbxm
-rojo build packages/vide-charm -o build/vide-charm.rbxm
+rojo build pkgs/charm -o build/charm.rbxm
+rojo build pkgs/charm-sync -o build/charm-sync.rbxm
+rojo build pkgs/react-charm -o build/react-charm.rbxm
+rojo build pkgs/vide-charm -o build/vide-charm.rbxm

bin/test.sh

@@ -1 +0,0 @@
-lute tests/spec.server.luau

default.project.json

@@ -6,15 +6,26 @@
 			"$className": "ReplicatedStorage",
 			"Packages": {
 				"$path": "roblox_packages",
-				"Charm": { "$path": "packages/charm" },
-				"CharmSync": { "$path": "packages/charm-sync" },
-				"ReactCharm": { "$path": "packages/react-charm" },
-				"VideCharm": { "$path": "packages/vide-charm" }
+				"Charm": { "$path": "pkgs/charm" },
+				"CharmSync": { "$path": "pkgs/charm-sync" },
+				"ReactCharm": { "$path": "pkgs/react-charm" },
+				"VideCharm": { "$path": "pkgs/vide-charm" }
 			}
 		},
 		"ServerScriptService": {
 			"$className": "ServerScriptService",
-			"Tests": { "$path": "tests" }
+			"Tests": {
+				"$path": "tests",
+				"Charm": { "$path": "pkgs/charm/__tests__" },
+				"CharmSync": { "$path": "pkgs/charm-sync/__tests__" },
+				"ReactCharm": { "$path": "pkgs/react-charm/__tests__" },
+				"VideCharm": { "$path": "pkgs/vide-charm/__tests__" }
+			},
+			"Benchmarks": {
+				"$className": "Folder",
+				"Charm": { "$path": "pkgs/charm/__benchmarks__" },
+				"CharmSync": { "$path": "pkgs/charm-sync/__benchmarks__" }
+			}
 		}
 	}
 }

packages/charm-sync/Charm.luau

@@ -1,2 +0,0 @@
---!nocheck
-return require(script.Parent.charm.src)

packages/charm/src/atom.luau

@@ -1,54 +0,0 @@
-local signals = require("./signals")
-local types = require("./types")
-
-type Atom<T> = types.Atom<T>
-type AtomOptions<T> = types.AtomOptions<T>
-
-local signal = signals.signal
-local pauseTracking = signals.pauseTracking
-local resumeTracking = signals.resumeTracking
-
-local function atomOper<T>(source: (...T) -> T, equals: ((T, T) -> boolean)?, ...: ((T) -> T) | T): T
-	if select("#", ...) == 0 then
-		return source()
-	end
-
-	local transform = (...)
-	local currentState = (source :: any).value
-	local nextState: T
-
-	-- If the transform is a function, call it with the current state and pause
-	-- tracking to avoid adding signals called by the transform.
-	if type(transform) == "function" then
-		pauseTracking()
-		local success, result = pcall(transform, currentState)
-		resumeTracking()
-
-		if not success then
-			error(result, 2)
-		end
-
-		nextState = result
-	else
-		nextState = transform
-	end
-
-	if equals and equals(currentState, nextState) then
-		return nextState
-	end
-
-	source(nextState)
-
-	return nextState
-end
-
-local function atom<T>(state: T, options: AtomOptions<T>?): Atom<T>
-	local source = signal(state)
-	local equals = options and options.equals
-
-	return function(...)
-		return atomOper(source, equals, ...)
-	end
-end
-
-return atom

packages/charm/src/effect.luau

@@ -1,27 +0,0 @@
-local signals = require("./signals")
-
-local effectImpl = signals.effect
-
-local function effect(callback: (dispose: () -> ()) -> ...() -> ()?): () -> ()
-	local disposed = false
-	local dispose: () -> ()
-
-	local function disposeSafe()
-		disposed = true
-		if dispose then
-			dispose()
-		end
-	end
-
-	dispose = effectImpl(function()
-		return callback(disposeSafe)
-	end)
-
-	if disposed then
-		dispose()
-	end
-
-	return disposeSafe
-end
-
-return effect

packages/charm/src/observe.luau

@@ -1,38 +0,0 @@
-local listen = require("./listen")
-
-local function observe<K, V>(selector: () -> { [K]: V }, observer: (item: V, key: K) -> ...() -> ()?): () -> ()
-	local cleanups: { [K]: () -> ()? } = {}
-
-	local unsub = listen(selector, function(currentItems, previousItems)
-		if not previousItems then
-			for key, value in currentItems do
-				cleanups[key] = observer(value, key)
-			end
-			return
-		end
-
-		for key in previousItems do
-			local cleanup = cleanups[key]
-			if currentItems[key] == nil and cleanup then
-				cleanups[key] = nil
-				cleanup()
-			end
-		end
-
-		for key, value in currentItems do
-			if previousItems[key] == nil then
-				cleanups[key] = observer(value, key)
-			end
-		end
-	end)
-
-	return function()
-		unsub()
-		for _, cleanup in cleanups do
-			(cleanup :: () -> ())()
-		end
-		table.clear(cleanups)
-	end
-end
-
-return observe

packages/react-charm/Charm.luau

@@ -1,2 +0,0 @@
---!nocheck
-return require(script.Parent.charm.src)

packages/react-charm/React.luau

@@ -1,2 +0,0 @@
---!nocheck
-return require(script.Parent.react)

packages/vide-charm/Charm.luau

@@ -1,2 +0,0 @@
---!nocheck
-return require(script.Parent.charm.src)

packages/vide-charm/Vide.luau

@@ -1,2 +0,0 @@
---!nocheck
-return require(script.Parent.vide.src)

pkgs/charm-sync/__benchmarks__/patch.bench.luau

@@ -24,14 +24,18 @@ local function update(state)
 	state.users = table.clone(state.users)
 
 	for user = 1, USERS do
-		if math.random() > 0.5 then
-			continue
-		end
+		local rng = math.random()
 
-		state.users[user] = {
-			coins = math.random(1, 2),
-			gems = math.random(1, 2),
-		}
+		if rng < 1 / 3 then
+			continue
+		elseif rng < 2 / 3 then
+			state.users[user] = nil
+		else
+			state.users[user] = {
+				coins = math.random(1, 2),
+				gems = math.random(1, 2),
+			}
+		end
 	end
 
 	return state

pkgs/charm-sync/__tests__/spec.luau

@@ -0,0 +1,19 @@
+local ServerScriptService = game:GetService("ServerScriptService")
+
+local suite = require(ServerScriptService.Tests.suite)
+
+local describe = suite.describe
+
+local function spec(name: string)
+	describe(name, function()
+		return require(`./{name}.spec`) :: any
+	end)
+end
+
+spec("client")
+spec("server")
+spec("flatten")
+spec("patch")
+spec("validate")
+
+return {}

pkgs/charm/__benchmarks__/effect.bench.luau

@@ -6,17 +6,12 @@ local computed = Charm.computed
 local effect = Charm.effect
 local atom = Charm.atom
 
-local cleanup: () -> ()
-
 return {
-	AfterEach = function()
-		cleanup()
-	end,
 	Functions = {
 		atom = function()
 			local state = atom(0)
 
-			cleanup = effect(function()
+			effect(function()
 				state()
 			end)
 
@@ -32,7 +27,7 @@ return {
 				return 2 * state()
 			end)
 
-			cleanup = effect(function()
+			effect(function()
 				double()
 			end)
 

pkgs/charm/__benchmarks__/propagate.bench.luau

@@ -0,0 +1,63 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+
+local Charm = require(ReplicatedStorage.Packages.Charm)
+
+local atom = Charm.atom
+local computed = Charm.computed
+local effect = Charm.effect
+local listen = Charm.listen
+
+local function propagate(w: number, h: number)
+	local src = atom(1)
+	for _ = 1, w do
+		local last = src
+		for _ = 1, h do
+			local prev = last
+			last = computed(function()
+				return prev() + 1
+			end)
+		end
+		effect(function()
+			last()
+		end)
+	end
+	src(src() + 1)
+end
+
+local function propagateListen(w: number, h: number)
+	local src = atom(1)
+	for _ = 1, w do
+		local last = src
+		for _ = 1, h do
+			local prev = last
+			last = computed(function()
+				return prev() + 1
+			end)
+		end
+		listen(last, function() end)
+	end
+	src(src() + 1)
+end
+
+return {
+	Functions = {
+		["effect 1*100"] = function()
+			propagate(1, 100)
+		end,
+		["effect 100*1"] = function()
+			propagate(100, 1)
+		end,
+		["effect 10*10"] = function()
+			propagate(10, 10)
+		end,
+		["listen 1*100"] = function()
+			propagateListen(1, 100)
+		end,
+		["listen 100*1"] = function()
+			propagateListen(100, 1)
+		end,
+		["listen 10*10"] = function()
+			propagateListen(10, 10)
+		end,
+	},
+}

pkgs/charm/__tests__/signals/computed.spec.luau

@@ -1,13 +1,12 @@
-local charm = require("../charm")
-local suite = require("../suite")
+local signals = require("../../src/signals")
+local suite = require("@tests/suite")
 
-local signals = charm.signals
 local computed = signals.computed
 local signal = signals.signal
 local test = suite.test
 
 test("should correctly propagate changes through computed signals", function()
-	local src = signal(0)
+	local src, setSrc = signal(0)
 	local c1 = computed(function()
 		return src() % 2
 	end)
@@ -19,15 +18,15 @@ test("should correctly propagate changes through computed signals", function()
 	end)
 
 	c3()
-	src(1) -- c1 -> dirty, c2 -> toCheckDirty, c3 -> toCheckDirty
+	setSrc(1) -- c1 -> dirty, c2 -> toCheckDirty, c3 -> toCheckDirty
 	c2() -- c1 -> none, c2 -> none
-	src(3) -- c1 -> dirty, c2 -> toCheckDirty
+	setSrc(3) -- c1 -> dirty, c2 -> toCheckDirty
 
 	assert(c3() == 1, "bad final value")
 end)
 
 test("should propagate updated source value through chained computations", function()
-	local src = signal(0)
+	local src, setSrc = signal(0)
 	local a = computed(function()
 		return src()
 	end)
@@ -42,12 +41,12 @@ test("should propagate updated source value through chained computations", funct
 	end)
 
 	assert(d() == 0, "bad initial value")
-	src(2)
+	setSrc(2)
 	assert(d() == 2, "bad updated value")
 end)
 
 test("should handle flags are indirectly updated during checkDirty", function()
-	local a = signal(false)
+	local a, setA = signal(false)
 	local b = computed(function()
 		return a()
 	end)
@@ -61,22 +60,22 @@ test("should handle flags are indirectly updated during checkDirty", function()
 	end)
 
 	assert(d() == false, "bad initial value")
-	a(true)
+	setA(true)
 	assert(d() == true, "bad updated value")
 end)
 
 test("should not update if the signal value is reverted", function()
 	local times = 0
 
-	local src = signal(0)
+	local src, setSrc = signal(0)
 	local c1 = computed(function()
 		times += 1
 		return src()
 	end)
 	c1()
 	assert(times == 1, "computed did not run")
-	src(1)
-	src(0)
+	setSrc(1)
+	setSrc(0)
 	c1()
 	assert(times == 1, "computed ran when it should not")
 end)

pkgs/charm/__tests__/signals/effect.spec.luau

@@ -1,13 +1,13 @@
-local charm = require("../charm")
-local suite = require("../suite")
+local signals = require("../../src/signals")
+local suite = require("@tests/suite")
 
-local signals = charm.signals
 local computed = signals.computed
 local effect = signals.effect
 local effectScope = signals.effectScope
 local endBatch = signals.endBatch
 local pauseTracking = signals.pauseTracking
 local resumeTracking = signals.resumeTracking
+local onEffectCleanup = signals.onEffectCleanup
 local signal = signals.signal
 local startBatch = signals.startBatch
 local test = suite.test
@@ -15,7 +15,7 @@ local test = suite.test
 test("should clear subscriptions when untracked by all subscribers", function()
 	local bRunTimes = 0
 
-	local a = signal(1)
+	local a, setA = signal(1)
 	local b = computed(function()
 		bRunTimes += 1
 		return a() * 2
@@ -25,15 +25,15 @@ test("should clear subscriptions when untracked by all subscribers", function()
 	end)
 
 	assert(bRunTimes == 1, "should run initially")
-	a(2)
+	setA(2)
 	assert(bRunTimes == 2, "should run after change")
 	stopEffect()
-	a(3)
+	setA(3)
 	assert(bRunTimes == 2, "should not run after stop")
 end)
 
 test("should not run untracked inner effect", function()
-	local a = signal(3)
+	local a, setA = signal(3)
 	local b = computed(function()
 		return a() > 0
 	end)
@@ -48,14 +48,14 @@ test("should not run untracked inner effect", function()
 		end
 	end)
 
-	a(2)
-	a(1)
-	a(0)
+	setA(2)
+	setA(1)
+	setA(0)
 end)
 
 test("should run outer effect first", function()
-	local a = signal(1)
-	local b = signal(1)
+	local a, setA = signal(1)
+	local b, setB = signal(1)
 
 	effect(function()
 		if a() > 0 then
@@ -69,13 +69,13 @@ test("should run outer effect first", function()
 	end)
 
 	startBatch()
-	b(0)
-	a(0)
+	setB(0)
+	setA(0)
 	endBatch()
 end)
 
 test("should not trigger inner effect when resolve maybe dirty", function()
-	local a = signal(0)
+	local a, setA = signal(0)
 	local b = computed(function()
 		return a() % 2
 	end)
@@ -92,12 +92,12 @@ test("should not trigger inner effect when resolve maybe dirty", function()
 		end)
 	end)
 
-	a(2)
+	setA(2)
 end)
 
 test("should trigger inner effects in sequence", function()
-	local a = signal(0)
-	local b = signal(0)
+	local a, setA = signal(0)
+	local b, setB = signal(0)
 	local c = computed(function()
 		return a() - b()
 	end)
@@ -121,16 +121,16 @@ test("should trigger inner effects in sequence", function()
 	table.clear(order)
 
 	startBatch()
-	b(1)
-	a(1)
+	setB(1)
+	setA(1)
 	endBatch()
 
 	assert(table.concat(order, ", ") == "first inner, last inner", `wrong order: {table.concat(order, ", ")}`)
 end)
 
 test("should trigger inner effects in sequence in effect scope", function()
-	local a = signal(0)
-	local b = signal(0)
+	local a, setA = signal(0)
+	local b, setB = signal(0)
 	local order: { string } = {}
 
 	effectScope(function()
@@ -149,8 +149,8 @@ test("should trigger inner effects in sequence in effect scope", function()
 	table.clear(order)
 
 	startBatch()
-	b(1)
-	a(1)
+	setB(1)
+	setA(1)
 	endBatch()
 
 	assert(table.concat(order, ", ") == "first inner, last inner", `wrong order: {table.concat(order, ", ")}`)
@@ -170,12 +170,12 @@ test("should custom effect support batch", function()
 
 	local logs: { string } = {}
 	local a = signal(0)
-	local b = signal(0)
+	local b, setB = signal(0)
 
 	local aa = computed(function()
 		table.insert(logs, "aa-0")
 		if a() == 0 then
-			b(1)
+			setB(1)
 		end
 		table.insert(logs, "aa-1")
 		return nil
@@ -197,8 +197,8 @@ test("should custom effect support batch", function()
 end)
 
 test("should duplicate subscribers do not affect the notify order", function()
-	local src1 = signal(0)
-	local src2 = signal(0)
+	local src1, setSrc1 = signal(0)
+	local src2, setSrc2 = signal(0)
 	local order: { string } = {}
 
 	effect(function()
@@ -216,17 +216,17 @@ test("should duplicate subscribers do not affect the notify order", function()
 		table.insert(order, "b")
 		src1()
 	end)
-	src2(1) -- src1.subs: a -> b -> a
+	setSrc2(1) -- src1.subs: a -> b -> a
 
 	table.clear(order)
-	src1(src1() + 1)
+	setSrc1(src1() + 1)
 
 	assert(table.concat(order) == "ab", `wrong order: {table.concat(order)}`)
 end)
 
 test("should handle side effect with inner effects", function()
-	local a = signal(0)
-	local b = signal(0)
+	local a, setA = signal(0)
+	local b, setB = signal(0)
 	local order: { string } = {}
 
 	effect(function()
@@ -241,14 +241,14 @@ test("should handle side effect with inner effects", function()
 		assert(table.concat(order) == "ab", `wrong order: {table.concat(order)}`)
 
 		table.clear(order)
-		b(1)
-		a(1)
+		setB(1)
+		setA(1)
 		assert(table.concat(order) == "ba", `wrong order: {table.concat(order)}`)
 	end)
 end)
 
 test("should handle flags are indirectly updated during checkDirty", function()
-	local a = signal(false)
+	local a, setA = signal(false)
 	local b = computed(function()
 		return a()
 	end)
@@ -268,71 +268,57 @@ test("should handle flags are indirectly updated during checkDirty", function()
 		triggers += 1
 	end)
 	assert(triggers == 1, "did not run initially")
-	a(true)
+	setA(true)
 	assert(triggers == 2, "did not update indirectly")
 end)
 
-test("should run effect cleanup", function()
-	local cleanups = 0
+test("should run cleanups in sequence", function()
+	local order = {}
 
-	local a = signal(false)
-	local cleanup = effect(function()
+	local a, setA = signal(false)
+	local stopEffect = effect(function()
 		a()
-		return function()
-			cleanups += 1
-		end
-	end)
-
-	assert(cleanups == 0, "should not cleanup immediately")
-	a(true)
-	assert(cleanups == 1, "should cleanup once")
-	cleanup()
-	assert(cleanups == 2, "should cleanup after effect stop")
-	a(false)
-	assert(cleanups == 2, "should not cleanup after update")
-end)
-
-test("should run inner effect cleanup in scope", function()
-	local cleanups = 0
-
-	local a = signal(false)
-	local stopScope = effectScope(function()
-		effect(function()
-			a()
-			return function()
-				cleanups += 1
-			end
+		onEffectCleanup(function()
+			table.insert(order, "a")
+		end)
+		onEffectCleanup(function()
+			table.insert(order, "b")
 		end)
 	end)
 
-	assert(cleanups == 0, "should not cleanup immediately")
-	a(true)
-	assert(cleanups == 1, "should cleanup once")
-	stopScope()
-	assert(cleanups == 2, "should cleanup after outer dispose")
-	a(false)
-	assert(cleanups == 2, "should not cleanup after update")
+	assert(table.concat(order) == "", "should not cleanup immediately")
+
+	setA(true)
+	assert(table.concat(order) == "ab", `bad update: {table.concat(order)}`)
+
+	table.clear(order)
+	stopEffect()
+	assert(table.concat(order) == "ab", `bad dispose: {table.concat(order)}`)
+
+	table.clear(order)
+	setA(false)
+	assert(table.concat(order) == "", "should not cleanup after update")
 end)
 
 test("should run inner effect cleanup", function()
 	local cleanups = 0
 
-	local a = signal(false)
-	local stopScope = effect(function()
+	local a, setA = signal(false)
+	local stopEffect = effect(function()
 		a()
 		effect(function()
-			return function()
+			onEffectCleanup(function()
 				cleanups += 1
-			end
+			end)
 		end)
 	end)
 
 	assert(cleanups == 0, "should not cleanup immediately")
-	a(true)
+	setA(true)
 	assert(cleanups == 1, "should cleanup after outer update")
-	stopScope()
+	stopEffect()
 	assert(cleanups == 2, "should cleanup after outer dispose")
-	a(false)
+	setA(false)
 	assert(cleanups == 2, "should not cleanup after update")
 end)
 

pkgs/charm/__tests__/signals/effectScope.spec.luau

@@ -1,14 +1,15 @@
-local charm = require("../charm")
-local suite = require("../suite")
+local signals = require("../../src/signals")
+local suite = require("@tests/suite")
 
-local signals = charm.signals
 local effect = signals.effect
 local effectScope = signals.effectScope
 local signal = signals.signal
+local onEffectCleanup = signals.onEffectCleanup
+local onScopeDispose = signals.onScopeDispose
 local test = suite.test
 
 test("should not trigger after stop", function()
-	local count = signal(1)
+	local count, setCount = signal(1)
 
 	local triggers = 0
 
@@ -19,42 +20,26 @@ test("should not trigger after stop", function()
 		end)
 		assert(triggers == 1, "did not run initially")
 
-		count(2)
+		setCount(2)
 		assert(triggers == 2, "did not run after update")
 	end)
 
-	count(3)
+	setCount(3)
 	assert(triggers == 3, "did not run after update outside scope")
 	stopScope()
-	count(4)
+	setCount(4)
 	assert(triggers == 3, "ran after stop")
 end)
 
-test("should run effect cleanup", function()
-	local cleanups = 0
-
-	local cleanup = effectScope(function()
-		return function()
-			cleanups += 1
-		end
-	end)
-
-	assert(cleanups == 0, "should not cleanup immediately")
-	cleanup()
-	assert(cleanups == 1, "should cleanup after effect stop")
-	cleanup()
-	assert(cleanups == 1, "should skip redundant cleanup")
-end)
-
-test("should run indirect effect cleanup", function()
+test("should run indirect scope cleanup", function()
 	local cleanups = 0
 
 	local cleanup
 	local stopScope = effectScope(function()
 		cleanup = effectScope(function()
-			return function()
+			onScopeDispose(function()
 				cleanups += 1
-			end
+			end)
 		end)
 	end)
 
@@ -65,4 +50,26 @@ test("should run indirect effect cleanup", function()
 	assert(cleanups == 1, "should skip redundant dispose")
 end)
 
+test("should run indirect effect cleanup", function()
+	local cleanups = 0
+
+	local a, setA = signal(false)
+	local stopScope = effectScope(function()
+		effect(function()
+			a()
+			onEffectCleanup(function()
+				cleanups += 1
+			end)
+		end)
+	end)
+
+	assert(cleanups == 0, "should not cleanup immediately")
+	setA(true)
+	assert(cleanups == 1, "should cleanup once")
+	stopScope()
+	assert(cleanups == 2, "should cleanup after outer dispose")
+	setA(false)
+	assert(cleanups == 2, "should not cleanup after update")
+end)
+
 return {}

pkgs/charm/__tests__/signals/issue_48.spec.luau

@@ -1,7 +1,6 @@
-local charm = require("../charm")
-local suite = require("../suite")
+local signals = require("../../src/signals")
+local suite = require("@tests/suite")
 
-local signals = charm.signals
 local computed = signals.computed
 local effect = signals.effect
 local pauseTracking = signals.pauseTracking
@@ -92,7 +91,7 @@ local function reaction<T>(
 end
 
 test("#48", function()
-	local source = signal(0)
+	local source, setSource = signal(0)
 	local disposeInner: () -> ()
 
 	reaction(function()
@@ -107,9 +106,9 @@ test("#48", function()
 		end
 	end)
 
-	source(1)
-	source(2)
-	source(3)
+	setSource(1)
+	setSource(2)
+	setSource(3)
 end)
 
 return {}

pkgs/charm/__tests__/signals/spec.luau

@@ -0,0 +1,18 @@
+local suite = require("@tests/suite")
+
+local describe = suite.describe
+
+local function spec(name: string)
+	describe(name, function()
+		return require(`./{name}.spec`) :: any
+	end)
+end
+
+spec("computed")
+spec("effect")
+spec("effectScope")
+spec("issue_48")
+spec("topology")
+spec("untrack")
+
+return {}

pkgs/charm/__tests__/signals/topology.spec.luau

@@ -1,7 +1,6 @@
-local charm = require("../charm")
-local suite = require("../suite")
+local signals = require("../../src/signals")
+local suite = require("@tests/suite")
 
-local signals = charm.signals
 local computed = signals.computed
 local effect = signals.effect
 local signal = signals.signal
@@ -44,7 +43,7 @@ describe("graph updates", function()
 		--     C
 		--     |
 		--     D
-		local a = signal(2)
+		local a, setA = signal(2)
 
 		local b = computed(function()
 			return a() - 1
@@ -65,7 +64,7 @@ describe("graph updates", function()
 		assert(computeCalls == 1, "compute should be called once")
 		computeCalls = 0
 
-		a(4)
+		setA(4)
 		d()
 		assert(computeCalls == 1, "compute should drop update")
 	end)
@@ -79,7 +78,7 @@ describe("graph updates", function()
 		--   \   /
 		--     D
 
-		local a = signal("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -97,7 +96,7 @@ describe("graph updates", function()
 		assert(d() == "a a", "d should be 'a a'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		a("aa")
+		setA("aa")
 		assert(d() == "aa aa", "d should be 'aa aa'")
 		assert(spyCalls == 2, "compute should be called only twice")
 	end)
@@ -112,7 +111,7 @@ describe("graph updates", function()
 		--     |
 		--     E
 
-		local a = signal("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -134,7 +133,7 @@ describe("graph updates", function()
 		assert(e() == "a a", "e should be 'a a'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		a("aa")
+		setA("aa")
 		assert(e() == "aa aa", "e should be 'aa aa'")
 		assert(spyCalls == 2, "compute should be called only twice")
 	end)
@@ -142,7 +141,7 @@ describe("graph updates", function()
 	test("should bail out if result is the same", function()
 		-- Bail out if value of "B" never changes
 		-- A->B->C
-		local a = signal("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			a()
 			return "foo"
@@ -158,7 +157,7 @@ describe("graph updates", function()
 		assert(c() == "foo", "c should be 'foo'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		a("aa")
+		setA("aa")
 		assert(c() == "foo", "c should be 'foo'")
 		assert(spyCalls == 1, "compute should bail out")
 	end)
@@ -174,7 +173,7 @@ describe("graph updates", function()
 		--     E
 		--   /   \
 		--  F     G
-		local a = signal("a")
+		local a, setA = signal("a")
 
 		local b = computed(function()
 			return a()
@@ -223,7 +222,7 @@ describe("graph updates", function()
 		fSpyCalls, fSpyTime = 0, 0
 		gSpyCalls, gSpyTime = 0, 0
 
-		a("b")
+		setA("b")
 
 		assert(e() == "b b", "e should be 'b b'")
 		assert(eSpyCalls == 1, "e should run once after update")
@@ -238,7 +237,7 @@ describe("graph updates", function()
 		fSpyCalls, fSpyTime = 0, 0
 		gSpyCalls, gSpyTime = 0, 0
 
-		a("c")
+		setA("c")
 
 		assert(e() == "c c", "e should be 'c c'")
 		assert(eSpyCalls == 1, "e should run once after update")
@@ -259,7 +258,7 @@ describe("graph updates", function()
 		--    *A
 		--   /   \
 		-- *B     C <- we don't listen to C
-		local a = signal("a")
+		local a, setA = signal("a")
 
 		local b = computed(function()
 			return a()
@@ -274,7 +273,7 @@ describe("graph updates", function()
 		assert(b() == "a", "b should be 'a'")
 		assert(spyCalls == 0, "compute should not run")
 
-		a("aa")
+		setA("aa")
 		assert(b() == "aa", "b should be 'aa'")
 		assert(spyCalls == 0, "compute should not run")
 	end)
@@ -288,7 +287,7 @@ describe("graph updates", function()
 		-- *B     D <- we don't listen to C
 		--  |
 		-- *C
-		local a = signal("a")
+		local a, setA = signal("a")
 		local spyBCalls = 0
 		local spyB = function()
 			spyBCalls += 1
@@ -319,7 +318,7 @@ describe("graph updates", function()
 		spyCCalls = 0
 		unsub()
 
-		a("aa")
+		setA("aa")
 
 		assert(spyBCalls == 0, "b should not run")
 		assert(spyCCalls == 0, "c should not run")
@@ -336,7 +335,7 @@ describe("graph updates", function()
 		--  B     *C <- returns same value every time
 		--   \   /
 		--     D
-		local a = signal("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -354,7 +353,7 @@ describe("graph updates", function()
 		assert(d() == "a c", "d should be 'a c'")
 		spyResult = nil
 
-		a("aa")
+		setA("aa")
 		d()
 		assert(spyResult == "aa c", "d should have returned 'aa c'")
 	end)
@@ -368,7 +367,7 @@ describe("graph updates", function()
 		--  B *C *D
 		--   \ | /
 		--     E
-		local a = signal("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -390,13 +389,13 @@ describe("graph updates", function()
 		assert(e() == "a c d", "e should be 'a c d'")
 		spyResult = nil
 
-		a("aa")
+		setA("aa")
 		e()
 		assert(spyResult == "aa c d", "e should have returned 'aa c d'")
 	end)
 
 	test("should support lazy branches", function()
-		local a = signal(0)
+		local a, setA = signal(0)
 		local b = computed(function()
 			return a()
 		end)
@@ -405,10 +404,10 @@ describe("graph updates", function()
 		end)
 
 		assert(c() == 0, "c should be 0")
-		a(1)
+		setA(1)
 		assert(c() == 1, "c should be 1")
 
-		a(0)
+		setA(0)
 		assert(c() == 0, "c should be 0 again")
 	end)
 
@@ -420,7 +419,7 @@ describe("graph updates", function()
 		-- *B     *C
 		--   \   /
 		--     D
-		local a = signal("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			a()
 			return "b"
@@ -439,14 +438,14 @@ describe("graph updates", function()
 		assert(d() == "b c", "d should be 'b c'")
 		spyCalls = 0
 
-		a("aa")
+		setA("aa")
 		assert(spyCalls == 0, "d should not run")
 	end)
 end)
 
 describe("error handling", function()
 	test("should keep graph consistent on errors during activation", function()
-		local a = signal(0)
+		local a, setA = signal(0)
 		local b = computed(function()
 			error("fail")
 		end)
@@ -460,12 +459,12 @@ describe("error handling", function()
 		assert(not success, "should throw")
 		assert(string.match(result, "fail"), "should throw fail")
 
-		a(1)
+		setA(1)
 		assert(c() == 1, "c should recover and return 1")
 	end)
 
 	test("should keep graph consistent on errors in computeds", function()
-		local a = signal(0)
+		local a, setA = signal(0)
 		local b = computed(function()
 			if a() == 1 then
 				error("fail")
@@ -478,14 +477,14 @@ describe("error handling", function()
 
 		assert(c() == 0, "c should be 0")
 
-		a(1)
+		setA(1)
 		local success, result = pcall(function()
 			b()
 		end)
 		assert(not success, "should throw")
 		assert(string.match(result, "fail"), "should throw fail")
 
-		a(2)
+		setA(2)
 		assert(c() == 2, "c should recover and return 2")
 	end)
 end)

pkgs/charm/__tests__/signals/untrack.spec.luau

@@ -1,7 +1,6 @@
-local charm = require("../charm")
-local suite = require("../suite")
+local signals = require("../../src/signals")
+local suite = require("@tests/suite")
 
-local signals = charm.signals
 local computed = signals.computed
 local pauseTracking = signals.pauseTracking
 local resumeTracking = signals.resumeTracking
@@ -9,7 +8,7 @@ local signal = signals.signal
 local test = suite.test
 
 test("should pause tracking", function()
-	local src = signal(0)
+	local src, setSrc = signal(0)
 	local c = computed(function()
 		pauseTracking()
 		local value = src()
@@ -18,7 +17,7 @@ test("should pause tracking", function()
 	end)
 	assert(c() == 0, "should not track src")
 
-	src(1)
+	setSrc(1)
 	assert(c() == 0, "should not track src")
 end)
 

pkgs/charm/__tests__/spec.luau

@@ -0,0 +1,20 @@
+local suite = require("@tests/suite")
+
+local describe = suite.describe
+
+local function collect(name: string)
+	describe(name, function()
+		return require(`./{name}/spec`) :: any
+	end)
+end
+
+local function spec(name: string)
+	describe(name, function()
+		return require(`./{name}.spec`) :: any
+	end)
+end
+
+collect("signals")
+spec("subscribe")
+
+return {}

pkgs/charm/__tests__/subscribe.spec.luau

@@ -0,0 +1,28 @@
+local atom = require("../src/atom")
+local subscribe = require("../src/subscribe")
+local suite = require("@tests/suite")
+
+local test = suite.test
+
+test("should subscribe to atom", function()
+	local source = atom(0)
+	local current, previous
+
+	local unsub = subscribe(source, function(a, b)
+		current = a
+		previous = b
+	end)
+
+	assert(not current and not previous, "should not run initially")
+	source(1)
+	assert(current == 1, "should run with new value")
+	assert(previous == 0, "should run with old value")
+	source(2)
+	assert(current == 2, "should run with new value 2")
+	assert(previous == 1, "should run with old value 2")
+	unsub()
+	source(3)
+	assert(current == 2, "should not run after unsubscribing")
+end)
+
+return {}

pkgs/charm/src/atom.luau

@@ -0,0 +1,54 @@
+local signals = require("./signals")
+local types = require("./types")
+
+type Atom<T> = types.Atom<T>
+type AtomOptions<T> = types.AtomOptions<T>
+
+local signal = signals.signal
+
+local function atomGetterSetterEquals<T>(
+	source: () -> T,
+	setSource: (((T) -> T) | T) -> T,
+	equals: (T, T) -> boolean
+): Atom<T>
+	return function(...: ((T) -> T) | T): T
+		if select("#", ...) == 0 then
+			return source()
+		end
+
+		local nextState = (...)
+
+		if type(nextState) == "function" then
+			return setSource(function(currentState): T
+				local nextState = nextState(currentState)
+				return if equals(currentState, nextState) then currentState else nextState
+			end)
+		else
+			return setSource(function(currentState): T
+				return if equals(currentState, nextState) then currentState else nextState
+			end)
+		end
+	end
+end
+
+local function atomGetterSetter<T>(source: () -> T, setSource: (((T) -> T) | T) -> T): Atom<T>
+	return function(...: ((T) -> T) | T): T
+		if select("#", ...) == 0 then
+			return source()
+		else
+			return setSource((...))
+		end
+	end
+end
+
+local function atom<T>(state: T, equals: ((previous: T, current: T) -> boolean)?): Atom<T>
+	local source, setSource = signal(state)
+
+	if equals then
+		return atomGetterSetterEquals(source, setSource, equals)
+	else
+		return atomGetterSetter(source, setSource)
+	end
+end
+
+return atom

pkgs/charm/src/effect.luau

@@ -0,0 +1,27 @@
+local signals = require("./signals")
+
+local _effect = signals.effect
+local onEffectCleanup = signals.onEffectCleanup
+
+local function effect(callback: (dispose: () -> ()) -> ...() -> ()?): () -> ()
+	local disposeImmediately = false
+
+	local function dispose()
+		disposeImmediately = true
+	end
+
+	dispose = _effect(function()
+		local cleanup = callback(dispose)
+		if cleanup then
+			onEffectCleanup(cleanup)
+		end
+	end)
+
+	if disposeImmediately then
+		dispose()
+	end
+
+	return dispose
+end
+
+return effect

pkgs/charm/src/effectScope.luau

@@ -0,0 +1,15 @@
+local signals = require("./signals")
+
+local _effectScope = signals.effectScope
+local onScopeDispose = signals.onScopeDispose
+
+local function effectScope(callback: () -> ...() -> ()?): () -> ()
+	return _effectScope(function()
+		local cleanup = callback()
+		if cleanup then
+			onScopeDispose(cleanup)
+		end
+	end)
+end
+
+return effectScope

pkgs/charm/src/lib.luau

@@ -15,6 +15,8 @@ export type Selector<T = any> = types.Selector<T>
 
 local computed = signals.computed
 local effectScope = signals.effectScope
+local onEffectCleanup = signals.onEffectCleanup
+local onScopeDispose = signals.onScopeDispose
 
 return {
 	atom = atom,
@@ -27,5 +29,7 @@ return {
 	observe = observe,
 	subscribe = subscribe,
 	untracked = untracked,
+	onEffectCleanup = onEffectCleanup,
+	onScopeDispose = onScopeDispose,
 	signals = signals,
 }

pkgs/charm/src/listen.luau

@@ -6,40 +6,31 @@ local pauseTracking = signals.pauseTracking
 local resumeTracking = signals.resumeTracking
 
 local function listen<T>(selector: () -> T, listener: (state: T, previous: T?, dispose: () -> ()) -> ()): () -> ()
-	local disposed = false
-	local mounted = true
+	local disposeImmediately = false
 	local current: T?
-	local dispose: () -> ()
 
-	local function disposeSafe()
-		disposed = true
-		if dispose then
-			dispose()
-		end
+	local function dispose()
+		disposeImmediately = true
 	end
 
 	dispose = effect(function()
 		local value = selector()
 
-		if mounted then
-			mounted = false
-		elseif value == current then
-			return
+		if value ~= current then
+			local previous = current
+			current = value
+
+			pauseTracking()
+			spawn(listener, value, previous, dispose)
+			resumeTracking()
 		end
-
-		local previous = current
-		current = value
-
-		pauseTracking()
-		spawn(listener, value, previous, disposeSafe)
-		resumeTracking()
 	end)
 
-	if disposed then
+	if disposeImmediately then
 		dispose()
 	end
 
-	return disposeSafe
+	return dispose
 end
 
 return listen

pkgs/charm/src/mapped.luau

@@ -19,7 +19,7 @@ local function mapped<KI, VI, KO, VO>(selector: () -> { [KI]: VI }, transform: (
 		resumeTracking()
 
 		if not success then
-			error(`observe() transform function failed: {valueOut}`)
+			error(`mapped() transform function failed: {valueOut}`)
 		end
 
 		return valueOut, keyOut
@@ -47,6 +47,10 @@ local function mapped<KI, VI, KO, VO>(selector: () -> { [KI]: VI }, transform: (
 			return mappedItems
 		end
 
+		if previousItems == currentItems then
+			return previousMappedItems
+		end
+
 		local mappedItems = table.clone(previousMappedItems)
 
 		-- Update and remove mapped keys if the source values changed

pkgs/charm/src/observe.luau

@@ -0,0 +1,60 @@
+local signals = require("./signals")
+
+local computed = signals.computed
+local effect = signals.effect
+local getCurrentSub = signals.getCurrentSub
+local onEffectCleanup = signals.onEffectCleanup
+local onScopeDispose = signals.onScopeDispose
+
+local function noop() end
+
+local function observe<K, V>(selector: () -> { [K]: V }, observer: (item: V, key: K) -> ...() -> ()?): () -> ()
+	local tracked = computed(function()
+		return selector()
+	end)
+
+	local cleanups: { [K]: () -> () } = {}
+	local currentItems: { [K]: V } = {}
+
+	local function update(currentItems: { [K]: V }, previousItems: { [K]: V })
+		for key in previousItems do
+			local cleanup = cleanups[key]
+			if currentItems[key] == nil and cleanup then
+				cleanups[key] = nil
+				cleanup()
+			end
+		end
+
+		for key, value in currentItems do
+			if previousItems[key] == nil then
+				cleanups[key] = observer(value, key) or noop
+			end
+		end
+	end
+
+	local function teardown()
+		for _, cleanup in cleanups do
+			cleanup()
+		end
+		table.clear(cleanups)
+	end
+
+	local disposeEffect = effect(function()
+		local previousItems = currentItems
+		currentItems = tracked()
+		update(currentItems, previousItems)
+	end)
+
+	if getCurrentSub() then
+		onEffectCleanup(teardown)
+	else
+		onScopeDispose(teardown)
+	end
+
+	return function()
+		disposeEffect()
+		teardown()
+	end
+end
+
+return observe

pkgs/charm/src/signals.luau

@@ -1,5 +1,5 @@
 --[=[
-	alien-signals 2.0.1 implementation with effect cleanups, adopted from
+	alien-signals 2.0.1 implementation adopted from
 	https://github.com/Nicell/alien-signals-luau
 	https://github.com/stackblitz/alien-signals
 
@@ -47,7 +47,7 @@ type EffectScope = ReactiveNode & {
 }
 
 type Effect = ReactiveNode & {
-	fn: () -> (() -> ())?,
+	fn: () -> (),
 	cleanup: (() -> ())?,
 }
 
@@ -100,26 +100,36 @@ local function setCurrentScope(scope: EffectScope?)
 	return prevScope
 end
 
-local function pauseTracking()
-	pauseStackCount += 1
-	pauseStack[pauseStackCount] = activeSub
-	activeSub = nil
+local function addCleanup(e: EffectScope, cleanup: () -> ())
+	local prevCleanup = e.cleanup
+	if prevCleanup then
+		e.cleanup = function()
+			prevCleanup()
+			cleanup()
+		end
+	else
+		e.cleanup = cleanup
+	end
 end
 
-local function resumeTracking()
-	activeSub = pauseStack[pauseStackCount]
-	pauseStack[pauseStackCount] = nil
-	pauseStackCount -= 1
+local function onEffectCleanup(cleanup: () -> ())
+	if activeSub then
+		addCleanup(activeSub :: Effect, cleanup)
+	end
 end
 
-local function cleanup(e: ReactiveNode)
-	local e = e :: EffectScope
-	local cleanup = e.cleanup
-	if cleanup then
-		e.cleanup = nil
+local function onScopeDispose(cleanup: () -> ())
+	if activeScope then
+		addCleanup(activeScope, cleanup)
+	end
+end
+
+local function cleanupEffect(e: EffectScope)
+	if e.cleanup then
 		local prev = setCurrentSub(nil)
-		local success, result: unknown = pcall(cleanup)
+		local success, result: unknown = pcall(e.cleanup)
 		setCurrentSub(prev)
+		e.cleanup = nil
 		if not success then
 			error(result)
 		end
@@ -128,16 +138,15 @@ end
 
 local function run(e: EffectScope, flags: ReactiveFlags): ()
 	if bit32.band(flags, DIRTY) ~= 0 or (bit32.band(flags, PENDING) ~= 0 and checkDirty(e.deps :: Link, e)) then
-		cleanup(e)
+		cleanupEffect(e)
 		local prev = setCurrentSub(e)
 		startTracking(e)
-		local success, result = pcall((e :: Effect).fn)
+		local success, result: unknown = pcall((e :: Effect).fn)
 		setCurrentSub(prev)
 		endTracking(e)
 		if not success then
 			error(result)
 		end
-		e.cleanup = result
 		return
 	elseif bit32.band(flags, PENDING) ~= 0 then
 		e.flags = bit32.band(flags, bit32.bnot(PENDING))
@@ -182,6 +191,18 @@ local function endBatch()
 	end
 end
 
+local function pauseTracking()
+	pauseStackCount += 1
+	pauseStack[pauseStackCount] = activeSub
+	activeSub = nil
+end
+
+local function resumeTracking()
+	activeSub = pauseStack[pauseStackCount]
+	pauseStack[pauseStackCount] = nil
+	pauseStackCount -= 1
+end
+
 local function updateComputed(c: Computed): boolean
 	local prevSub = setCurrentSub(c)
 	startTracking(c)
@@ -210,22 +231,8 @@ local function updateSignal(s: Signal, value: any): boolean
 	end
 end
 
-local function signalOper<T>(this: Signal<T>, ...: T): T?
-	if select("#", ...) > 0 then
-		local newValue = (...)
-		if this.value ~= newValue then
-			this.value = newValue
-			this.flags = bit32.bor(MUTABLE, DIRTY)
-			local subs = this.subs
-			if subs then
-				propagate(subs)
-				if batchDepth == 0 then
-					flush()
-				end
-			end
-		end
-		return
-	else
+local function signalGetterSetter<T>(this: Signal<T>): (() -> T, (value: ((T) -> T) | T) -> T)
+	local function getter(): T
 		local value = this.value
 		if bit32.band(this.flags, DIRTY) ~= 0 then
 			if updateSignal(this, value) then
@@ -240,64 +247,93 @@ local function signalOper<T>(this: Signal<T>, ...: T): T?
 		end
 		return value
 	end
-end
 
-local function computedOper<T>(this: Computed<T>): T
-	local flags = this.flags
-	if bit32.band(flags, DIRTY) ~= 0 or (bit32.band(flags, PENDING) ~= 0 and checkDirty(this.deps :: Link, this)) then
-		if updateComputed(this) then
+	local function setter(newValue: ((T) -> T) | T): T
+		local value = this.value
+		local newValue = newValue :: T
+		if type(newValue) == "function" then
+			local prev = setCurrentSub(nil)
+			local success, result = pcall(newValue, value)
+			setCurrentSub(prev)
+			if not success then
+				error(result)
+			end
+			newValue = result
+		end
+		if value ~= newValue then
+			this.value = newValue
+			this.flags = bit32.bor(MUTABLE, DIRTY)
 			local subs = this.subs
 			if subs then
-				shallowPropagate(subs)
+				propagate(subs)
+				if batchDepth == 0 then
+					flush()
+				end
 			end
 		end
-	elseif bit32.band(flags, PENDING) ~= 0 then
-		this.flags = bit32.band(flags, bit32.bnot(PENDING))
+		return newValue
 	end
-	if activeSub then
-		link(this, activeSub)
-	elseif activeScope then
-		link(this, activeScope)
-	end
-	return this.value :: T
+
+	return getter, setter
 end
 
-local function effectOper(this: EffectScope): ()
-	local dep = this.deps
-	while dep do
-		dep = unlink(dep, this)
+local function computedGetter<T>(this: Computed<T>): () -> T
+	return function()
+		local flags = this.flags
+		if
+			bit32.band(flags, DIRTY) ~= 0
+			or (bit32.band(flags, PENDING) ~= 0 and checkDirty(this.deps :: Link, this))
+		then
+			if updateComputed(this) then
+				local subs = this.subs
+				if subs then
+					shallowPropagate(subs)
+				end
+			end
+		elseif bit32.band(flags, PENDING) ~= 0 then
+			this.flags = bit32.band(flags, bit32.bnot(PENDING))
+		end
+		if activeSub then
+			link(this, activeSub)
+		elseif activeScope then
+			link(this, activeScope)
+		end
+		return this.value :: T
 	end
-	local sub = this.subs
-	while sub do
-		unlink(sub)
-		sub = this.subs
-	end
-	this.flags = NONE
-	cleanup(this)
 end
 
-local signalMetatable = { __call = signalOper }
-local computedMetatable = { __call = computedOper }
-local effectMetatable = { __call = effectOper }
+local function effectStop(this: EffectScope): () -> ()
+	return function()
+		local dep = this.deps
+		while dep do
+			dep = unlink(dep, this)
+		end
+		local sub = this.subs
+		while sub do
+			unlink(sub)
+			sub = this.subs
+		end
+		this.flags = NONE
+		cleanupEffect(this)
+	end
+end
 
-local function signal<T>(initialValue: T): ((T) -> ()) & (() -> T)
-	local this: Signal<T> = {
+local function signal<T>(initialValue: T): (() -> T, (value: ((T) -> T) | T) -> T)
+	return signalGetterSetter({
 		previousValue = initialValue,
 		value = initialValue,
 		flags = MUTABLE,
-	}
-	return setmetatable(this, signalMetatable) :: any
+	})
 end
 
 local function computed<T>(getter: (previousValue: T?) -> T): () -> T
-	local this: Computed<T> = {
+	return computedGetter({
 		flags = bit32.bor(MUTABLE, DIRTY),
 		getter = getter,
-	}
-	return setmetatable(this, computedMetatable) :: any
+	})
 end
 
-local function effect(fn: () -> ...() -> ()?): () -> ()
+local function effect(fn: () -> ()): () -> ()
 	local e: Effect = {
 		fn = fn,
 		flags = WATCHING,
@@ -308,16 +344,15 @@ local function effect(fn: () -> ...() -> ()?): () -> ()
 		link(e, activeScope)
 	end
 	local prev = setCurrentSub(e)
-	local success, result = pcall(fn)
+	local success, result: unknown = pcall(fn)
 	setCurrentSub(prev)
 	if not success then
 		error(result)
 	end
-	e.cleanup = result
-	return setmetatable(e, effectMetatable) :: any
+	return effectStop(e)
 end
 
-local function effectScope(fn: () -> ...() -> ()?): () -> ()
+local function effectScope(fn: () -> ()): () -> ()
 	local e: EffectScope = {
 		flags = NONE,
 	}
@@ -325,13 +360,12 @@ local function effectScope(fn: () -> ...() -> ()?): () -> ()
 		link(e, activeScope)
 	end
 	local prev = setCurrentScope(e)
-	local success, result = pcall(fn)
+	local success, result: unknown = pcall(fn)
 	setCurrentScope(prev)
 	if not success then
 		error(result)
 	end
-	e.cleanup = result
-	return setmetatable(e, effectMetatable) :: any
+	return effectStop(e)
 end
 
 local function notify(e: ReactiveNode)
@@ -343,7 +377,7 @@ local function notify(e: ReactiveNode)
 			notify(subs.sub :: Effect | EffectScope)
 		else
 			queuedEffectsLength += 1
-			queuedEffects[queuedEffectsLength] = e :: Effect | EffectScope
+			queuedEffects[queuedEffectsLength] = e :: Effect
 		end
 	end
 end
@@ -364,7 +398,7 @@ local function unwatched(signal: ReactiveNode)
 		until not toRemove
 		signal.flags = bit32.bor(signal.flags, DIRTY)
 	end
-	cleanup(signal)
+	cleanupEffect(signal :: EffectScope)
 end
 
 local reactiveSystem = createReactiveSystem({
@@ -393,6 +427,8 @@ return {
 	endBatch = endBatch,
 	pauseTracking = pauseTracking,
 	resumeTracking = resumeTracking,
+	onEffectCleanup = onEffectCleanup,
+	onScopeDispose = onScopeDispose,
 	signal = signal,
 	computed = computed,
 	effect = effect,

pkgs/charm/src/subscribe.luau

@@ -8,9 +8,8 @@ local resumeTracking = signals.resumeTracking
 local function subscribe<T>(selector: () -> T, listener: (T, T) -> ()): () -> ()
 	local current: T
 	local mounted = true
-	local dispose: () -> ()
 
-	dispose = effect(function()
+	return effect(function()
 		local value = selector()
 
 		if mounted then
@@ -25,10 +24,6 @@ local function subscribe<T>(selector: () -> T, listener: (T, T) -> ()): () -> ()
 			resumeTracking()
 		end
 	end)
-
-	return function()
-		dispose()
-	end
 end
 
 return subscribe

pkgs/react-charm/__tests__/spec.luau

@@ -0,0 +1,15 @@
+local ServerScriptService = game:GetService("ServerScriptService")
+
+local suite = require(ServerScriptService.Tests.suite)
+
+local describe = suite.describe
+
+local function spec(name: string)
+	describe(name, function()
+		return require(`./{name}.spec`) :: any
+	end)
+end
+
+spec("useAtom")
+
+return {}

pkgs/react-charm/__tests__/useAtom.spec.luau

@@ -3,7 +3,7 @@ local ServerScriptService = game:GetService("ServerScriptService")
 
 local Charm = require(ReplicatedStorage.Packages.Charm)
 local ReactCharm = require(ReplicatedStorage.Packages.ReactCharm)
-local renderHook = require(ServerScriptService.Tests.utils.renderHook)
+local renderHook = require(script.Parent.helpers.renderHook)
 local suite = require(ServerScriptService.Tests.suite)
 
 local atom = Charm.atom

pkgs/vide-charm/__tests__/spec.luau

@@ -0,0 +1,15 @@
+local ServerScriptService = game:GetService("ServerScriptService")
+
+local suite = require(ServerScriptService.Tests.suite)
+
+local describe = suite.describe
+
+local function spec(name: string)
+	describe(name, function()
+		return require(`./{name}.spec`) :: any
+	end)
+end
+
+spec("useAtom")
+
+return {}

tests/benchmarks/propagate.bench.luau

@@ -1,39 +0,0 @@
-local ReplicatedStorage = game:GetService("ReplicatedStorage")
-
-local Charm = require(ReplicatedStorage.Packages.Charm)
-
-local signals = Charm.signals
-
-local function propagate(
-	signal: <T>(T) -> (T?) -> T,
-	computed: <T>(() -> T) -> () -> T,
-	effect: (() -> ()) -> (),
-	w: number,
-	h: number
-)
-	local src = signal(1)
-	for _ = 1, w do
-		local last = src
-		for _ = 1, h do
-			local prev = last
-			last = computed(function()
-				return prev() + 1
-			end)
-		end
-		effect(function()
-			last()
-		end)
-	end
-	src(src() + 1)
-end
-
-return {
-	Functions = {
-		charm = function()
-			propagate(Charm.atom, Charm.computed, Charm.effect, 10, 10)
-		end,
-		alien_signals = function()
-			propagate(signals.signal, signals.computed, signals.effect, 10, 10)
-		end,
-	},
-}

tests/benchmarks/propagate.luau

@@ -1,59 +0,0 @@
-local Charm = require("../charm")
-
-local atom = Charm.atom
-local computed = Charm.computed
-local effect = Charm.effect
-
-local signal = Charm.signals.signal
-local computedSignal = Charm.signals.computed
-local effectSignal = Charm.signals.effect
-
-local w = 10
-local h = 10
-
-local function bench(name: string, test: () -> ())
-	local start = os.clock()
-	local iter = 0
-	for _ = 1, 15000 do
-		iter += 1
-		test()
-	end
-	local endTime = os.clock()
-	local elapsed = endTime - start
-	print(`{name}: {elapsed / iter * 1000 * 1000} us/iter`)
-end
-
-bench(`charm {w} * {h}`, function()
-	local src = atom(1)
-	for _ = 1, w do
-		local last = src
-		for _ = 1, h do
-			local prev = last
-			last = computed(function()
-				return prev() + 1
-			end)
-		end
-		effect(function()
-			last()
-		end)
-	end
-	src(src() + 1)
-end)
-
-bench(`alien-signals {w} * {h}`, function()
-	local src = signal(1)
-	for _ = 1, w do
-		local last = src
-		for _ = 1, h do
-			local prev = last
-			last = computedSignal(function()
-				return prev() + 1
-			end)
-		end
-		effectSignal(function()
-			last()
-			return nil
-		end)
-	end
-	src(src() + 1)
-end)

tests/charm-sync/spec.luau

@@ -1,17 +0,0 @@
-local suite = require("../suite")
-
-local describe = suite.describe
-
-local function test(name: string)
-	describe(name, function()
-		return require(`./{name}.spec`) :: any
-	end)
-end
-
-test("client")
-test("server")
-test("flatten")
-test("patch")
-test("validate")
-
-return {}

tests/charm.luau

@@ -1,3 +0,0 @@
-return if game
-	then require(game:GetService("ReplicatedStorage").Packages.Charm)
-	else require("../packages/charm/src/lib")

tests/init.luau

@@ -0,0 +1,14 @@
+local suite = require("@tests/suite")
+
+local describe = suite.describe
+local finish = suite.finish
+
+if not table.isfrozen(_G) then
+	_G.__DEV__ = true
+end
+
+describe("charm", function()
+	require("@pkgs/charm/__tests__/spec")
+end)
+
+finish()

tests/react-charm/spec.luau

@@ -1,13 +0,0 @@
-local suite = require("../suite")
-
-local describe = suite.describe
-
-local function test(name: string)
-	describe(name, function()
-		return require(`./{name}.spec`) :: any
-	end)
-end
-
-test("useAtom")
-
-return {}

tests/signals/spec.luau

@@ -1,18 +0,0 @@
-local suite = require("../suite")
-
-local describe = suite.describe
-
-local function test(name: string)
-	describe(name, function()
-		return require(`./{name}.spec`) :: any
-	end)
-end
-
-test("computed")
-test("effect")
-test("effectScope")
-test("issue_48")
-test("topology")
-test("untrack")
-
-return {}

tests/spec.server.luau

@@ -3,19 +3,18 @@ local suite = require("./suite")
 local describe = suite.describe
 local finish = suite.finish
 
-local function test(name: string)
-	describe(name, function()
-		return require(`./{name}/spec`) :: any
-	end)
-end
+_G.__DEV__ = true
 
-test("signals")
+describe("charm-sync", function()
+	require(script.Parent.CharmSync.spec)
+end)
 
-if game then
-	_G.__DEV__ = true
-	test("charm-sync")
-	test("react-charm")
-	test("vide-charm")
-end
+describe("react-charm", function()
+	require(script.Parent.ReactCharm.spec)
+end)
+
+describe("vide-charm", function()
+	require(script.Parent.VideCharm.spec)
+end)
 
 finish()

tests/utils/collect.luau

@@ -1,12 +0,0 @@
---[=[
-	Trigger a garbage collection cycle by allocating a large amount of junk memory
-	and then waiting for the next frame.
-]=]
-local function collect()
-	for _ = 1, 1e4 do
-		local _ = table.create(1e3)
-	end
-	task.wait()
-end
-
-return collect

tests/utils/count.luau

@@ -1,15 +0,0 @@
---[=[
-	Counts the number of elements in a table.
-
-	@param object The table to count.
-	@return The number of elements in the table.
-]=]
-local function count(object: any): number
-	local count = 0
-	for _ in next, object do
-		count += 1
-	end
-	return count
-end
-
-return count

tests/vide-charm/spec.luau

@@ -1,13 +0,0 @@
-local suite = require("../suite")
-
-local describe = suite.describe
-
-local function test(name: string)
-	describe(name, function()
-		return require(`./{name}.spec`) :: any
-	end)
-end
-
-test("useAtom")
-
-return {}