perf: optimize mapped, add benches

benchmarks/mapped.bench.luau

@@ -0,0 +1,99 @@
+--!optimize 2
+
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+
+local Charm = require(ReplicatedStorage.Packages.Charm)
+
+local atom = Charm.atom
+local computed = Charm.computed
+local mapped = Charm.mapped
+local pauseTracking = Charm.signals.pauseTracking
+local resumeTracking = Charm.signals.resumeTracking
+
+type Entry = { number }
+
+local count = 512
+local initialState: { Entry } = table.create(count)
+
+for i = 1, count do
+	initialState[i] = table.create(32, i)
+end
+
+local function mapper(value: Entry): Entry
+	return table.clone(value)
+end
+
+local function simpleMapped(source: () -> { Entry }): () -> { Entry }
+	return computed(function()
+		local state = source()
+		local nextState = {}
+
+		for index, value in state do
+			pauseTracking()
+			local success, valueOut = pcall(mapper, value)
+			resumeTracking()
+
+			if success then
+				nextState[index] = valueOut
+			end
+		end
+
+		return state
+	end)
+end
+
+local function updatePercentage(percent: number): ({ Entry }) -> { Entry }
+	return function(state)
+		local nextState = table.clone(state)
+		for index, value in state do
+			if math.random() < percent then
+				nextState[index] = table.clone(value)
+			end
+		end
+		return nextState
+	end
+end
+
+local function test(
+	percent: number,
+	profiler: any,
+	mapped: (src: () -> { Entry }, ...(Entry) -> Entry) -> () -> { Entry }
+)
+	local src = atom(initialState)
+	local out = mapped(src, mapper)
+
+	profiler.Begin("init")
+	out()
+	profiler.End()
+
+	profiler.Begin("setup")
+	src(updatePercentage(percent))
+	profiler.End()
+
+	profiler.Begin("update")
+	out()
+	profiler.End()
+end
+
+return {
+	Functions = {
+		["mapped 10%"] = function(profiler)
+			test(0.1, profiler, mapped)
+		end,
+		["mapped 50%"] = function(profiler)
+			test(0.5, profiler, mapped)
+		end,
+		["mapped 100%"] = function(profiler)
+			test(1, profiler, mapped)
+		end,
+		["control 10%"] = function(profiler)
+			test(0.1, profiler, simpleMapped)
+		end,
+		["control 50%"] = function(profiler)
+			test(0.5, profiler, simpleMapped)
+		end,
+		["control 100%"] = function(profiler)
+			test(1, profiler, simpleMapped)
+		end,
+	},
+}