refactor: rename batch, misc fixes & perf updates

packages/charm-sync/src/client.luau

@@ -65,9 +65,9 @@ end
 local function hydrate(payloads: { SyncPayload })
 	for _, payload in payloads do
 		if payload.type == "init" then
-			Charm.batched(applyInitPayload, payload.data)
+			Charm.batch(applyInitPayload, payload.data)
 		elseif payload.type == "patch" then
-			Charm.batched(applyPatchPayload, payload.data)
+			Charm.batch(applyPatchPayload, payload.data)
 		end
 	end
 end

packages/charm/src/__tests__/computed.spec.luau

@@ -1,5 +1,5 @@
-local core = require("../../core")
-local suite = require("../../../../../test/suite")
+local core = require("../core")
+local suite = require("../../../../test/suite")
 
 local computed = core.computed
 local effect = core.effect

packages/charm/src/__tests__/effect.spec.luau

@@ -1,5 +1,5 @@
-local core = require("../../core")
-local suite = require("../../../../../test/suite")
+local core = require("../core")
+local suite = require("../../../../test/suite")
 
 local computed = core.computed
 local effect = core.effect

packages/charm/src/__tests__/effectScope.spec.luau

@@ -1,5 +1,5 @@
-local core = require("../../core")
-local suite = require("../../../../../test/suite")
+local core = require("../core")
+local suite = require("../../../../test/suite")
 
 local effect = core.effect
 local effectScope = core.effectScope

packages/charm/src/__tests__/gc.spec.luau

@@ -1,5 +1,5 @@
-local core = require("../../core")
-local suite = require("../../../../../test/suite")
+local core = require("../core")
+local suite = require("../../../../test/suite")
 
 local atom = core.atom
 local computed = core.computed

packages/charm/src/__tests__/observe.spec.luau

@@ -4,6 +4,7 @@ local suite = require("../../../../test/suite")
 local signal = Charm.signal
 local computed = Charm.computed
 local effect = Charm.effect
+local effectScope = Charm.effectScope
 local observe = Charm.observe
 local test = suite.test
 
@@ -42,48 +43,44 @@ test("should dispose scopes", function()
 	local items, setItems = signal({ 1, 2, 3 })
 	local a, setA = signal(0)
 	local runs = {}
+	local disposes = {}
 
 	local dispose = observe(items, function(item)
 		effect(function()
 			table.insert(runs, item)
 			a()
 		end)
+		effectScope(function()
+			return function()
+				table.insert(disposes, item)
+			end
+		end)
 	end)
 
 	table.clear(runs)
 	setItems({ 1, 2 })
 	setA(1)
 	assert(table.concat(runs) == "12", `bad reruns: {table.concat(runs)}`)
+	assert(table.concat(disposes) == "3", `should dispose 3: {table.concat(disposes)}`)
 
 	table.clear(runs)
+	table.clear(disposes)
 	dispose()
 	setA(2)
 	assert(table.concat(runs) == "", `should not rerun: {table.concat(runs)}`)
+	assert(table.concat(disposes) == "12", `should dispose 1 and 2: {table.concat(disposes)}`)
 end)
 
-test("should queue addition", function()
+test("should queue addition and removal", function()
 	local items, setItems = signal({ 1 })
 	local edits = {}
 
 	observe(items, function(item)
-		setItems({ 1, 2 })
-		setItems({ 1, 2, 3, 4 })
-		table.insert(edits, `+{item}`)
-		return function()
-			table.insert(edits, `-{item}`)
+		if item == 1 then
+			setItems({ 1, 2, 3, 4 })
+		elseif item == 4 then
+			setItems({ 1 })
 		end
-	end)
-
-	assert(table.concat(edits) == "+1+2+3+4", `bad edits: {table.concat(edits)}`)
-end)
-
-test("should queue removal", function()
-	local items, setItems = signal({ 1, 2, 3, 4 })
-	local edits = {}
-
-	observe(items, function(item)
-		setItems({ 1, 2, 3 })
-		setItems({ 1 })
 		table.insert(edits, `+{item}`)
 		return function()
 			table.insert(edits, `-{item}`)
@@ -93,4 +90,23 @@ test("should queue removal", function()
 	assert(table.concat(edits) == "+1+2+3+4-2-3-4", `bad edits: {table.concat(edits)}`)
 end)
 
+test("should handle self removal", function()
+	local items, setItems = signal({ 1, 2, 3, 4 })
+	local edits = {}
+
+	observe(items, function(item, index)
+		setItems(function(state)
+			state = table.clone(state)
+			state[index] = nil
+			return state
+		end)
+		table.insert(edits, `+{item}`)
+		return function()
+			table.insert(edits, `-{item}`)
+		end
+	end)
+
+	assert(table.concat(edits) == "+1+2+3+4-1-2-3-4", `bad edits: {table.concat(edits)}`)
+end)
+
 return {}

packages/charm/src/__tests__/signal.spec.luau

@@ -1,5 +1,5 @@
-local core = require("../../core")
-local suite = require("../../../../../test/suite")
+local core = require("../core")
+local suite = require("../../../../test/suite")
 
 local signal = core.signal
 local effect = core.effect
@@ -37,4 +37,14 @@ test("should enforce immutability", function()
 	end), "should not allow mutation of new value")
 end)
 
+test("should not freeze values with metatables", function()
+	local src = signal({ object = setmetatable({}, {}) })
+	assert(
+		pcall(function()
+			src().object.a = 2
+		end),
+		"should allow mutation of values with metatables"
+	)
+end)
+
 return {}

packages/charm/src/__tests__/spec.luau

@@ -1,26 +1,17 @@
 local suite = require("../../../../test/suite")
 
-suite.describe("core", function()
-	suite.describe("computed", function()
-		require("./core/computed.spec")
-	end)
-	suite.describe("effect", function()
-		require("./core/effect.spec")
-	end)
-	suite.describe("effectScope", function()
-		require("./core/effectScope.spec")
-	end)
-	suite.describe("gc", function()
-		require("./core/gc.spec")
-	end)
-	suite.describe("signal", function()
-		require("./core/signal.spec")
-	end)
-	suite.describe("topology", function()
-		require("./core/topology.spec")
-	end)
+suite.describe("computed", function()
+	require("./computed.spec")
+end)
+suite.describe("effect", function()
+	require("./effect.spec")
+end)
+suite.describe("effectScope", function()
+	require("./effectScope.spec")
+end)
+suite.describe("gc", function()
+	require("./gc.spec")
 end)
-
 suite.describe("listen", function()
 	require("./listen.spec")
 end)
@@ -30,14 +21,20 @@ end)
 suite.describe("observe", function()
 	require("./observe.spec")
 end)
+suite.describe("peek", function()
+	require("./peek.spec")
+end)
+suite.describe("signal", function()
+	require("./signal.spec")
+end)
 suite.describe("subscribe", function()
 	require("./subscribe.spec")
 end)
+suite.describe("topology", function()
+	require("./topology.spec")
+end)
 suite.describe("untracked", function()
 	require("./untracked.spec")
 end)
-suite.describe("peek", function()
-	require("./peek.spec")
-end)
 
 return {}

packages/charm/src/__tests__/topology.spec.luau

@@ -1,9 +1,9 @@
-local core = require("../../core")
-local suite = require("../../../../../test/suite")
+local core = require("../core")
+local suite = require("../../../../test/suite")
 
+local atom = core.atom
 local computed = core.computed
 local effect = core.effect
-local signal = core.signal
 local describe = suite.describe
 local test = suite.test
 
@@ -43,7 +43,7 @@ describe("graph updates", function()
 		--     C
 		--     |
 		--     D
-		local a, setA = signal(2)
+		local a = atom(2)
 
 		local b = computed(function()
 			return a() - 1
@@ -64,7 +64,7 @@ describe("graph updates", function()
 		assert(computeCalls == 1, "compute should be called once")
 		computeCalls = 0
 
-		setA(4)
+		a(4)
 		d()
 		assert(computeCalls == 1, "compute should drop update")
 	end)
@@ -77,7 +77,7 @@ describe("graph updates", function()
 		--  B     C
 		--   \   /
 		--     D
-		local a, setA = signal("a")
+		local a = atom("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -95,7 +95,7 @@ describe("graph updates", function()
 		assert(d() == "a a", "d should be 'a a'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		setA("aa")
+		a("aa")
 		assert(d() == "aa aa", "d should be 'aa aa'")
 		assert(spyCalls == 2, "compute should be called only twice")
 	end)
@@ -109,7 +109,7 @@ describe("graph updates", function()
 		--     D
 		--     |
 		--     E
-		local a, setA = signal("a")
+		local a = atom("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -131,7 +131,7 @@ describe("graph updates", function()
 		assert(e() == "a a", "e should be 'a a'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		setA("aa")
+		a("aa")
 		assert(e() == "aa aa", "e should be 'aa aa'")
 		assert(spyCalls == 2, "compute should be called only twice")
 	end)
@@ -139,7 +139,7 @@ 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, setA = signal("a")
+		local a = atom("a")
 		local b = computed(function()
 			a()
 			return "foo"
@@ -155,7 +155,7 @@ describe("graph updates", function()
 		assert(c() == "foo", "c should be 'foo'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		setA("aa")
+		a("aa")
 		assert(c() == "foo", "c should be 'foo'")
 		assert(spyCalls == 1, "compute should bail out")
 	end)
@@ -171,7 +171,7 @@ describe("graph updates", function()
 		--     E
 		--   /   \
 		--  F     G
-		local a, setA = signal("a")
+		local a = atom("a")
 
 		local b = computed(function()
 			return a()
@@ -220,7 +220,7 @@ describe("graph updates", function()
 		fSpyCalls, fSpyTime = 0, 0
 		gSpyCalls, gSpyTime = 0, 0
 
-		setA("b")
+		a("b")
 
 		assert(e() == "b b", "e should be 'b b'")
 		assert(eSpyCalls == 1, "e should run once after update")
@@ -235,7 +235,7 @@ describe("graph updates", function()
 		fSpyCalls, fSpyTime = 0, 0
 		gSpyCalls, gSpyTime = 0, 0
 
-		setA("c")
+		a("c")
 
 		assert(e() == "c c", "e should be 'c c'")
 		assert(eSpyCalls == 1, "e should run once after update")
@@ -256,7 +256,7 @@ describe("graph updates", function()
 		--    *A
 		--   /   \
 		-- *B     C <- we don't listen to C
-		local a, setA = signal("a")
+		local a = atom("a")
 
 		local b = computed(function()
 			return a()
@@ -271,7 +271,7 @@ describe("graph updates", function()
 		assert(b() == "a", "b should be 'a'")
 		assert(spyCalls == 0, "compute should not run")
 
-		setA("aa")
+		a("aa")
 		assert(b() == "aa", "b should be 'aa'")
 		assert(spyCalls == 0, "compute should not run")
 	end)
@@ -285,7 +285,7 @@ describe("graph updates", function()
 		-- *B     D <- we don't listen to C
 		--  |
 		-- *C
-		local a, setA = signal("a")
+		local a = atom("a")
 		local spyBCalls = 0
 		local spyB = function()
 			spyBCalls += 1
@@ -316,7 +316,7 @@ describe("graph updates", function()
 		spyCCalls = 0
 		unsub()
 
-		setA("aa")
+		a("aa")
 
 		assert(spyBCalls == 0, "b should not run")
 		assert(spyCCalls == 0, "c should not run")
@@ -333,7 +333,7 @@ describe("graph updates", function()
 		--  B     *C <- returns same value every time
 		--   \   /
 		--     D
-		local a, setA = signal("a")
+		local a = atom("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -351,7 +351,7 @@ describe("graph updates", function()
 		assert(d() == "a c", "d should be 'a c'")
 		spyResult = nil
 
-		setA("aa")
+		a("aa")
 		d()
 		assert(spyResult == "aa c", "d should have returned 'aa c'")
 	end)
@@ -365,7 +365,7 @@ describe("graph updates", function()
 		--  B *C *D
 		--   \ | /
 		--     E
-		local a, setA = signal("a")
+		local a = atom("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -387,13 +387,13 @@ describe("graph updates", function()
 		assert(e() == "a c d", "e should be 'a c d'")
 		spyResult = nil
 
-		setA("aa")
+		a("aa")
 		e()
 		assert(spyResult == "aa c d", "e should have returned 'aa c d'")
 	end)
 
 	test("should support lazy branches", function()
-		local a, setA = signal(0)
+		local a = atom(0)
 		local b = computed(function()
 			return a()
 		end)
@@ -402,10 +402,10 @@ describe("graph updates", function()
 		end)
 
 		assert(c() == 0, "c should be 0")
-		setA(1)
+		a(1)
 		assert(c() == 1, "c should be 1")
 
-		setA(0)
+		a(0)
 		assert(c() == 0, "c should be 0 again")
 	end)
 
@@ -417,7 +417,7 @@ describe("graph updates", function()
 		-- *B     *C
 		--   \   /
 		--     D
-		local a, setA = signal("a")
+		local a = atom("a")
 		local b = computed(function()
 			a()
 			return "b"
@@ -436,14 +436,14 @@ describe("graph updates", function()
 		assert(d() == "b c", "d should be 'b c'")
 		spyCalls = 0
 
-		setA("aa")
+		a("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, setA = signal(0)
+		local a = atom(0)
 		local b = computed(function()
 			error("fail")
 		end)
@@ -457,12 +457,12 @@ describe("error handling", function()
 		assert(not success, "should throw")
 		assert(string.match(result, "fail"), "should throw fail")
 
-		setA(1)
+		a(1)
 		assert(c() == 1, "c should recover and return 1")
 	end)
 
 	test("should keep graph consistent on errors in computeds", function()
-		local a, setA = signal(0)
+		local a = atom(0)
 		local b = computed(function()
 			if a() == 1 then
 				error("fail")
@@ -475,14 +475,14 @@ describe("error handling", function()
 
 		assert(c() == 0, "c should be 0")
 
-		setA(1)
+		a(1)
 		local success, result = pcall(function()
 			b()
 		end)
 		assert(not success, "should throw")
 		assert(string.match(result, "fail"), "should throw fail")
 
-		setA(2)
+		a(2)
 		assert(c() == 2, "c should recover and return 2")
 	end)
 end)

packages/charm/src/alien.luau

@@ -167,21 +167,17 @@ local function createReactiveSystem(props: {
 	end
 
 	local function propagate(link: Link): ()
-		local next = link.nextSub
-		local stack: Stack<Link?>?
-
 		repeat
 			local sub = link.sub
-
 			local flags = sub.flags
 
-			if not bit32.btest(flags, bit32.bor(RECURSED_CHECK, RECURSED, DIRTY, PENDING)) then
+			if bit32.band(flags, bit32.bor(RECURSED_CHECK, RECURSED, DIRTY, PENDING)) == 0 then
 				sub.flags = bit32.bor(flags, PENDING)
-			elseif not bit32.btest(flags, bit32.bor(RECURSED_CHECK, RECURSED)) then
+			elseif bit32.band(flags, bit32.bor(RECURSED_CHECK, RECURSED)) == 0 then
 				flags = NONE
-			elseif not bit32.btest(flags, RECURSED_CHECK) then
+			elseif bit32.band(flags, RECURSED_CHECK) == 0 then
 				sub.flags = bit32.bor(bit32.band(flags, bit32.bnot(RECURSED)), PENDING)
-			elseif not bit32.btest(flags, bit32.bor(DIRTY, PENDING)) and isValidLink(link, sub) then
+			elseif bit32.band(flags, bit32.bor(DIRTY, PENDING)) == 0 and isValidLink(link, sub) then
 				sub.flags = bit32.bor(flags, bit32.bor(RECURSED, PENDING))
 				flags = bit32.band(flags, MUTABLE)
 			else
@@ -196,41 +192,12 @@ local function createReactiveSystem(props: {
 			if bit32.btest(flags, MUTABLE) then
 				local subSubs = sub.subs
 				if subSubs then
-					link = subSubs
-					local nextSub = link.nextSub
-					if nextSub then
-						stack = { value = next, prev = stack }
-						next = nextSub
-					end
-					continue
+					propagate(subSubs)
 				end
 			end
 
-			link = next :: Link
-
-			if link then
-				next = link.nextSub
-				continue
-			end
-
-			local continueTop = false
-
-			while stack do
-				link = stack.value :: Link
-				stack = stack.prev
-				if link then
-					next = link.nextSub
-					continueTop = true
-					break
-				end
-			end
-
-			if continueTop then
-				continue
-			end
-
-			break
-		until false
+			link = link.nextSub :: Link
+		until not link
 	end
 
 	local function shallowPropagate(link: Link): ()
@@ -248,81 +215,38 @@ local function createReactiveSystem(props: {
 	end
 
 	local function checkDirty(link: Link, sub: ReactiveNode): boolean
-		local stack: Stack<Link>?
-		local checkDepth = 0
-		local dirty = false
-
 		repeat
 			local dep = link.dep
-			local flags = dep.flags
+			local depFlags = dep.flags
 
 			if bit32.btest(sub.flags, DIRTY) then
-				dirty = true
-			elseif bit32.band(flags, bit32.bor(MUTABLE, DIRTY)) == bit32.bor(MUTABLE, DIRTY) then
+				return true
+			elseif bit32.band(depFlags, bit32.bor(MUTABLE, DIRTY)) == bit32.bor(MUTABLE, DIRTY) then
 				if update(dep) then
 					local subs = dep.subs :: Link
 					if subs.nextSub then
 						shallowPropagate(subs)
 					end
-					dirty = true
+					return true
 				end
-			elseif bit32.band(flags, bit32.bor(MUTABLE, PENDING)) == bit32.bor(MUTABLE, PENDING) then
-				if link.nextSub or link.prevSub then
-					stack = { value = link, prev = stack }
-				end
-				link = dep.deps :: Link
-				sub = dep
-				checkDepth += 1
-				continue
-			end
-
-			if not dirty then
-				local nextDep = link.nextDep
-				if nextDep then
-					link = nextDep
-					continue
-				end
-			end
-
-			local continueTop = false
-
-			while checkDepth ~= 0 do
-				checkDepth -= 1
-				local firstSub = sub.subs :: Link
-				local hasMultipleSubs = firstSub.nextSub ~= nil
-				if hasMultipleSubs then
-					link = (stack :: Stack<Link>).value
-					stack = (stack :: Stack<Link>).prev
-				else
-					link = firstSub
-				end
-				if dirty then
-					if update(sub) then
-						if hasMultipleSubs then
-							shallowPropagate(firstSub)
+			elseif bit32.band(depFlags, bit32.bor(MUTABLE, PENDING)) == bit32.bor(MUTABLE, PENDING) then
+				if checkDirty(dep.deps :: Link, dep) then
+					if update(dep) then
+						local subs = dep.subs :: Link
+						if subs.nextSub then
+							shallowPropagate(subs)
 						end
-						sub = link.sub
-						continue
+						return true
 					end
-					dirty = false
 				else
-					sub.flags = bit32.band(sub.flags, bit32.bnot(PENDING))
-				end
-				sub = link.sub
-				local nextDep = link.nextDep
-				if nextDep then
-					link = nextDep
-					continueTop = true
-					break
+					dep.flags = bit32.band(depFlags, bit32.bnot(PENDING))
 				end
 			end
 
-			if continueTop then
-				continue
-			end
+			link = link.nextDep :: Link
+		until not link
 
-			return dirty
-		until false
+		return false
 	end
 
 	return {

packages/charm/src/core.luau

@@ -235,7 +235,7 @@ local function signalOper<T>(
 		local value: T
 		if type(update) == "function" then
 			local prevSub = setActiveSub(nil)
-			local success, result: T = (if globals.strict then noYield else pcall)(update, this.currentValue)
+			local success, result: T = (if globals.strict then noYield else pcall)(update, this.pendingValue)
 			activeSub = prevSub
 			if not success then
 				error(result)
@@ -278,9 +278,7 @@ local function signalOper<T>(
 				break
 			end
 			local subs = sub.subs
-			if subs then
-				sub = subs.sub
-			end
+			sub = if subs then subs.sub else nil
 		end
 		return this.currentValue
 	end
@@ -434,17 +432,21 @@ end
 --- For an alternative that still cleans up inner effects, use `peek` instead.
 ---
 --- @param callback The callback function.
---- @param args Arguments to pass to the callback.
+--- @param ...args Arguments to pass to the callback.
 --- @return The return value of the callback.
 --- @see https://github.com/littensy/charm?tab=readme-ov-file#untrackedcallback
 local function untracked<Args..., Results...>(callback: (Args...) -> Results..., ...: Args...): Results...
-	local prevSub = setActiveSub(nil)
-	local results: { any } = { pcall(callback, ...) }
-	activeSub = prevSub
-	if not results[1] then
-		error(results[2])
+	if activeSub then
+		local prevSub = setActiveSub(nil)
+		local results: { any } = { pcall(callback, ...) }
+		activeSub = prevSub
+		if not results[1] then
+			error(results[2])
+		end
+		return unpack(results, 2)
+	else
+		return callback(...)
 	end
-	return unpack(results, 2)
 end
 
 --- Runs the callback without subscribing to signal updates, but still captures
@@ -453,7 +455,7 @@ end
 --- To avoid capturing inner effects, use `untracked` instead.
 ---
 --- @param callback The callback function.
---- @param args Arguments to pass to the callback.
+--- @param ...args Arguments to pass to the callback.
 --- @return The return value of the callback.
 --- @see https://github.com/littensy/charm?tab=readme-ov-file#peekcallback
 local function peek<Args..., Results...>(callback: (Args...) -> Results..., ...: Args...): Results...
@@ -478,10 +480,10 @@ end
 --- computed signals after the provided callback finishes running.
 ---
 --- @param callback A function that performs multiple updates.
---- @param args Arguments to pass to the callback.
+--- @param ...args Arguments to pass to the callback.
 --- @return The return value of the callback.
---- @see https://github.com/littensy/charm?tab=readme-ov-file#batchedcallback
-local function batched<Args..., Results...>(callback: (Args...) -> Results..., ...: Args...): Results...
+--- @see https://github.com/littensy/charm?tab=readme-ov-file#batchcallback
+local function batch<Args..., Results...>(callback: (Args...) -> Results..., ...: Args...): Results...
 	startBatch()
 	local results: { any } = { (if globals.strict then noYield else pcall)(callback, ...) }
 	endBatch()
@@ -497,7 +499,7 @@ end
 ---
 --- @param getter A function that returns the value to track.
 --- @return A computed signal that tracks the value returned by the getter.
-local function toComputed<T>(getter: () -> T): () -> T
+local function toSignal<T>(getter: () -> T): () -> T
 	local name = debug.info(getter, "n")
 	if name == "signalGetter" or name == "computedGetter" or name == "atomGetterSetter" then
 		return getter
@@ -519,7 +521,7 @@ end
 --- @return A function for disposing the effect.
 --- @see https://github.com/littensy/charm?tab=readme-ov-file#listengetter-callback
 local function listen<T>(getter: () -> T, callback: (state: T, previous: T?) -> ()): () -> ()
-	local tracked = toComputed(getter)
+	local tracked = toSignal(getter)
 	local current: T
 	return effect(function()
 		local previous = current
@@ -540,15 +542,12 @@ end
 --- @return A function for disposing the effect.
 --- @see https://github.com/littensy/charm?tab=readme-ov-file#subscribegetter-callback
 local function subscribe<T>(getter: () -> T, callback: (state: T, lastState: T) -> ()): () -> ()
-	local tracked = toComputed(getter)
-	local current: T
-	local mounted = true
+	local tracked = toSignal(getter)
+	local current = tracked()
 	return effect(function()
 		local previous = current
 		current = tracked()
-		if mounted then
-			mounted = false
-		else
+		if current ~= previous then
 			peek(callback, current, previous)
 		end
 	end)
@@ -578,12 +577,14 @@ local reactiveSystem = createReactiveSystem({
 
 		queuedLength = insertIndex
 
+		-- while (firstInsertedIndex < --insertIndex)
 		insertIndex -= 1
 		while firstInsertedIndex < insertIndex do
 			local left = queued[firstInsertedIndex]
 			queued[firstInsertedIndex] = queued[insertIndex]
 			queued[insertIndex] = left
 			firstInsertedIndex += 1
+			-- Decrement before next iteration to simulate --insertIndex
 			insertIndex -= 1
 		end
 	end,
@@ -620,7 +621,7 @@ return {
 	onCleanup = onCleanup,
 	untracked = untracked,
 	peek = peek,
-	batched = batched,
+	batch = batch,
 	subscribe = subscribe,
 	listen = listen,
 }

packages/charm/src/index.d.ts

@@ -149,9 +149,9 @@ export function peek<Args extends any[], Result>(callback: (...args: Args) => Re
  * @param callback A function that performs multiple updates.
  * @param args Arguments to pass to the callback.
  * @returns The return value of the callback.
- * @see https://github.com/littensy/charm?tab=readme-ov-file#batchedcallback
+ * @see https://github.com/littensy/charm?tab=readme-ov-file#batchcallback
  */
-export function batched<Args extends any[], Result>(callback: (...args: Args) => Result, ...args: Args): Result;
+export function batch<Args extends any[], Result>(callback: (...args: Args) => Result, ...args: Args): Result;
 
 /**
  * Creates an effect that runs the callback one immediately, and then again

packages/charm/src/init.luau

@@ -11,11 +11,22 @@ type Update<T> = ((previous: T) -> T) | T
 --- its current value.
 export type Atom<T = any> = (...Update<T>) -> T
 
+--- A getter-only reactive signal. Calling the signal with no arguments returns
+--- its current value. It cannot be set directly.
+export type Getter<T = any> = () -> T
+
+--- A setter-only reactive signal. Calling the signal with an argument sets its
+--- value. It cannot be read directly.
+export type Setter<T = any> = (...Update<T>) -> ()
+
+export type ReactiveNode = core.ReactiveNode
+export type Link = core.Link
+
 return {
 	core = core,
 	globals = globals,
 	atom = core.atom,
-	batched = core.batched,
+	batch = core.batch,
 	computed = core.computed,
 	effect = core.effect,
 	effectScope = core.effectScope,

packages/charm/src/observe.luau

@@ -1,70 +1,66 @@
 local core = require("./core")
-local globals = require("./globals")
 
-local batched = core.batched
+type ReactiveNode = core.ReactiveNode
+
+local batch = core.batch
 local effect = core.effect
 local effectScope = core.effectScope
-local onCleanup = core.onCleanup
 
 --- Calls the callback function for each unique key in the table returned by the
 --- getter. The callback is called once for each key, and again when a new key
 --- is added.
 ---
 --- The callback may return a cleanup function, which will be called when the
---- key is removed or when the entire callback is disposed.
----
---- Effects created within the callback are cleaned up when the item is removed
---- from the table or when the callback is disposed.
+--- key is removed or the `observe()` effect is disposed. Effects created
+--- during the callback will also be bound to the lifetime of the key.
 ---
 --- @param getter A function that returns the table to observe.
 --- @param callback A function that is called for each key in the table.
 --- @return A function for disposing the observer.
 --- @see https://github.com/littensy/charm?tab=readme-ov-file#observegetter-callback
 local function observe<K, V>(getter: () -> { [K]: V }, callback: (item: V, key: K) -> ...(() -> ())?): () -> ()
-	local scopes: { [K]: () -> () } = {}
-	local currentItems: { [K]: V } = {}
+	local innerScopes: { [K]: () -> () } = {}
 
-	local function updateScopes(currentItems: { [K]: V }, previousItems: { [K]: V })
-		for key in previousItems do
-			local dispose = scopes[key]
-			if currentItems[key] == nil and dispose then
+	local function updateScopes(data: { [K]: V })
+		for key, dispose in innerScopes do
+			if data[key] == nil then
+				innerScopes[key] = nil
 				dispose()
-				scopes[key] = nil
 			end
 		end
 
-		for key, value in currentItems do
-			if previousItems[key] == nil and scopes[key] == nil then
-				scopes[key] = effectScope(function()
+		for key, value in data do
+			if innerScopes[key] == nil then
+				-- Detach the inner scope from the parent effect to prevent
+				-- disposing when the effect re-runs.
+				innerScopes[key] = effectScope(function()
 					return callback(value, key)
 				end, true)
 			end
 		end
 	end
 
-	local function disposeScopes()
-		for _, dispose in scopes do
-			dispose()
-		end
-		table.clear(scopes)
-	end
+	return effectScope(function()
+		effect(function()
+			-- Batch so that side effects run after all scopes are created. This
+			-- ensures that a scope creating or removing items doesn't interfere
+			-- with the current update cycle.
+			batch(updateScopes, getter())
 
-	local disposeEffect = effect(function()
-		local previousItems = currentItems
-		currentItems = getter()
-		if currentItems ~= previousItems then
-			batched(updateScopes, currentItems, previousItems)
+			-- Effects can't trigger themselves more than once, so if a scope
+			-- creates or removes items, we need to check for updates again. The
+			-- way we do this abuses a weird property of signal accesses that
+			-- causes the effect to re-run.
+			getter()
+		end)
+
+		return function()
+			for _, dispose in innerScopes do
+				dispose()
+			end
+			table.clear(innerScopes)
 		end
 	end)
-
-	if globals.trackInnerEffects then
-		onCleanup(disposeScopes, true)
-	end
-
-	return function()
-		disposeEffect()
-		disposeScopes()
-	end
 end
 
 return observe

packages/charm/src/utils.luau

@@ -14,7 +14,7 @@ local function noYield<Args..., Results...>(callback: (Args...) -> Results..., .
 end
 
 local function deepFreeze(object: any)
-	if type(object) == "table" and not table.isfrozen(object) then
+	if type(object) == "table" and not table.isfrozen(object) and getmetatable(object) == nil then
 		table.freeze(object)
 		for _, value in object do
 			deepFreeze(value)