Return nil if nth is over count

Increment component records after registering
Support setting signal on cached Relation
2025-08-04 11:19:17 +00:00 · 2025-08-02 23:57:50 +02:00 · 2025-08-02 18:58:19 +02:00 · 2025-08-02 06:20:53 +02:00 · 2025-07-29 21:08:23 +02:00 · 2025-07-29 21:07:59 +02:00
35 changed files with 4273 additions and 2494 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -2,6 +2,20 @@
 ## Unreleased
 ### Added
 - `jecs.Exclusive` trait for making exclusive relationships.
 ### Changed
 - `jecs.ChildOf` to be an exclusive relationship, which means you can only have one `ChildOf` pair on an entity.
 ## 0.7.2
 ### Added
 - `jecs.entity_index_try_get_fast` back as to not break the observer addon.
 ### Fixed
 - A linting problem with the types for `quer:with` and `query:without`.
 ## 0.7.0
 ### Added
@ -10,7 +24,7 @@
 - `bulk_insert` and `bulk_remove` respectively for moving an entity to an archetype without intermediate steps.
 ### Changed
- The fields `archetype.records[id]` and `archetype.counts[id` have been removed from the archetype struct and been moved to the component record `component_index[id].records[archetype.id]` and `component_index[id].counts[archetype.id]` respectively.
+- The fields `archetype.records[id]` and `archetype.counts[id]` have been removed from the archetype struct and been moved to the component record `component_index[id].records[archetype.id]` and `component_index[id].counts[archetype.id]` respectively.
 - Removed the metatable `jecs.World`. Use `jecs.world()` to create your World.
 - Archetypes will no longer be garbage collected when invalidated, allowing them to be recycled to save a lot of performance during frequent deletion.
 - Removed `jecs.entity_index_try_get_fast`. Use `jecs.entity_index_try_get` instead.
--- a/addons/ob.luau
+++ b/addons/ob.luau
@ -0,0 +1,217 @@
 --!strict
 local jecs = require("@jecs")
 type World = jecs.World
 type Query<T...> = jecs.Query<T...>
 type Id<T=any> = jecs.Id<T>
 type Entity<T> = jecs.Entity<T>
 export type Iter<T...> = (Observer<T...>) -> () -> (jecs.Entity, T...)
 export type Observer<T...> = typeof(setmetatable(
 	{} :: {
 		iter: Iter<T...>,
 		entities: { Entity<nil> },
 		disconnect: (Observer<T...>) -> ()
 	},
 	{} :: {
 		__iter: Iter<T...>,
 	}
 ))
 local function observers_new<T...>(
 	query: Query<T...>,
 	callback: ((Entity<nil>, Id<any>, value: any?) -> ())?
 ): Observer<T...>
 	query:cached()
 	local world = (query :: Query<T...> & { world: World }).world
 	callback = callback
 	local archetypes = {}
 	local terms = query.ids
 	local first = terms[1]
 	local observers_on_create = world.observable[jecs.ArchetypeCreate][first]
 	local observer_on_create = observers_on_create[#observers_on_create]
 	observer_on_create.callback = function(archetype)
 		archetypes[archetype.id] = true
 	end
 	local observers_on_delete = world.observable[jecs.ArchetypeDelete][first]
 	local observer_on_delete = observers_on_delete[#observers_on_delete]
 	observer_on_delete.callback = function(archetype)
 		archetypes[archetype.id] = nil
 	end
 	local entity_index = world.entity_index :: any
 	local i = 0
 	local entities = {}
 	local function emplaced<T, a>(
 		entity: jecs.Entity<T>,
 		id: jecs.Id<a>,
 		value: a?
 	)
 		local r = entity_index.sparse_array[jecs.ECS_ID(entity)]
 		local archetype = r.archetype
 		if archetypes[archetype.id] then
 			i += 1
 			entities[i] = entity
 			if callback ~= nil then
 				callback(entity, id, value)
 			end
 		end
 	end
 	for _, term in terms do
 		if jecs.IS_PAIR(term) then
 			term = jecs.ECS_PAIR_FIRST(term)
 		end
 		world:added(term, emplaced)
 		world:changed(term, emplaced)
 	end
  	local function disconnect()
   		table.remove(observers_on_create, table.find(
     		observers_on_create,
       		observer_on_create
     	))
     	table.remove(observers_on_delete, table.find(
      		observers_on_delete,
        	observer_on_delete
       	))
   	end
    local function iter()
  		local row = i
  		return function()
 			if row == 0 then
     			i = 0
      			table.clear(entities)
      		end
           	local entity = entities[row]
           	row -= 1
           	return entity
        end
    end
  	local observer = {
   		disconnect = disconnect,
     	entities = entities,
     	__iter = iter,
      	iter = iter
   	}
    setmetatable(observer, observer)
    return (observer :: any) :: Observer<T...>
 end
 local function monitors_new<T...>(
 	query: Query<T...>,
 	callback: ((Entity<nil>, Id<any>, value: any?) -> ())?
 ): Observer<T...>
 	query:cached()
 	local world = (query :: Query<T...> & { world: World }).world
 	local archetypes = {}
 	local terms = query.ids
 	local first = terms[1]
 	local observers_on_create = world.observable[jecs.ArchetypeCreate][first]
 	local observer_on_create = observers_on_create[#observers_on_create]
 	observer_on_create.callback = function(archetype)
 		archetypes[archetype.id] = true
 	end
 	local observers_on_delete = world.observable[jecs.ArchetypeDelete][first]
 	local observer_on_delete = observers_on_delete[#observers_on_delete]
 	observer_on_delete.callback = function(archetype)
 		archetypes[archetype.id] = nil
 	end
 	local entity_index = world.entity_index :: any
 	local i = 0
 	local entities = {}
 	local function emplaced<T, a>(
 		entity: jecs.Entity<T>,
 		id: jecs.Id<a>,
 		value: a?
 	)
 		local r = jecs.entity_index_try_get_fast(
 			entity_index, entity :: any) :: jecs.Record
 		local archetype = r.archetype
 		if archetypes[archetype.id] then
 			i += 1
 			entities[i] = entity
 			if callback ~= nil then
 				callback(entity, jecs.OnAdd)
 			end
 		end
 	end
 	local function removed(entity: jecs.Entity, component: jecs.Id)
 		local EcsOnRemove = jecs.OnRemove :: jecs.Id
 		if callback ~= nil then
 			callback(entity, EcsOnRemove)
 		end
 	end
 	for _, term in terms do
 		if jecs.IS_PAIR(term) then
 			term = jecs.ECS_PAIR_FIRST(term)
 		end
 		world:added(term, emplaced)
 		world:removed(term, removed)
 	end
 	local function disconnect()
  		table.remove(observers_on_create, table.find(
 	  		observers_on_create,
 	    	observer_on_create
 	   	))
 	   	table.remove(observers_on_delete, table.find(
 	      	observers_on_delete,
 	       	observer_on_delete
       	))
   	end
    local function iter()
  		local row = i
  		return function()
 			if row == 0 then
     			i = 0
     			table.clear(entities)
      		end
           	local entity = entities[row]
           	row -= 1
           	return entity
        end
    end
 	local observer = {
  		disconnect = disconnect,
 	   	entities = entities,
 	   	__iter = iter,
       	iter = iter
   	}
    setmetatable(observer, observer)
    return (observer :: any) :: Observer<T...>
 end
 return {
 	monitor = monitors_new,
 	observer = observers_new
 }
--- a/addons/observers.luau
+++ b/addons/observers.luau
@ -1,268 +0,0 @@
 local jecs = require("@jecs")
 export type PatchedWorld = jecs.World & {
 	added: <T>(PatchedWorld, jecs.Id<T>, (e: jecs.Entity, id: jecs.Id, value: T) -> ()) -> () -> (),
 	removed: <T>(PatchedWorld, jecs.Id<T>, (e: jecs.Entity, id: jecs.Id) -> ()) -> () -> (),
 	changed: <T>(PatchedWorld, jecs.Id<T>, (e: jecs.Entity, id: jecs.Id, value: T) -> ()) -> () -> (),
 	observer: (
 		PatchedWorld,
 		any,
 		(jecs.Entity) -> ()
 	) -> (),
 	monitor: (
 		PatchedWorld,
 		any,
 		(jecs.Entity, jecs.Id) -> ()
 	) -> ()
 }
 local function observers_new(world, query, callback)
 	local terms = query.filter_with :: { jecs.Id }
 	if not terms then
 		local ids = query.ids
 		query.filter_with = ids
 		terms = ids
 	end
 	local entity_index = world.entity_index :: any
 	local function emplaced(entity, id, value)
 		local r = jecs.entity_index_try_get_fast(
 			entity_index, entity :: any)
 		if not r then
 			return
 		end
 		local archetype = r.archetype
 		if jecs.query_match(query, archetype) then
 			callback(entity)
 		end
 	end
 	for _, term in terms do
 		world:added(term, emplaced)
 		world:changed(term, emplaced)
 	end
 end
 local function join(world, component)
 	local sparse_array = {}
 	local dense_array = {}
 	local values = {}
 	local max_id = 0
 	world:added(component, function(entity, id, value)
 		max_id += 1
 		sparse_array[entity] = max_id
 		dense_array[max_id] = entity
 		values[max_id] = value
 	end)
 	world:removed(component, function(entity, id)
 		local e_swap = dense_array[max_id]
 		local v_swap = values[max_id]
 		local dense = sparse_array[entity]
 		dense_array[dense] = e_swap
 		values[dense] = v_swap
 		sparse_array[entity] = nil
 		dense_array[max_id] = nil
 		values[max_id] = nil
 		max_id -= 1
 	end)
 	world:changed(component, function(entity, id, value)
 		values[sparse_array[entity]] = value
 	end)
 	return function()
 		local i = max_id
 		return function(): ...any
 			i -= 1
 			if i == 0 then
 				return nil
 			end
 			local e = dense_array[i]
 			return e, values[i]
 		end
 	end
 end
 local function monitors_new(world, query, callback)
 	local terms = query.filter_with :: { jecs.Id }
 	if not terms then
 		local ids = query.ids
 		query.filter_with = ids
 		terms = ids
 	end
 	local entity_index = world.entity_index :: any
 	local function emplaced(entity: jecs.Entity)
 		local r = jecs.entity_index_try_get_fast(
 			entity_index, entity :: any)
 		if not r then
 			return
 		end
 		local archetype = r.archetype
 		if jecs.query_match(query, archetype) then
 			callback(entity, jecs.OnAdd)
 		end
 	end
 	local function removed(entity: jecs.Entity, component: jecs.Id)
 		local r = jecs.entity_index_try_get_fast(
 			entity_index, entity :: any)
 		if not r then
 			return
 		end
 		local archetype = r.archetype
 		if jecs.query_match(query, archetype) then
 			local EcsOnRemove = jecs.OnRemove :: jecs.Id
 			callback(entity, EcsOnRemove)
 		end
 	end
 	for _, term in terms do
 		world:added(term, emplaced)
 		world:removed(term, removed)
 	end
 end
 local function observers_add(world: jecs.World): PatchedWorld
 	type Signal = { [jecs.Entity]: { (...any) -> () } }
 	local world_mut = world :: jecs.World & {[string]: any}
 	local signals = {
 		added = {} :: Signal,
 		emplaced = {} :: Signal,
 		removed = {} :: Signal
 	}
 	world_mut.added = function<T>(
 		_: jecs.World,
 		component: jecs.Id<T>,
 		fn: (e: jecs.Entity, id: jecs.Id, value: T) -> ()
 	)
 		local listeners = signals.added[component]
 		if not listeners then
 			listeners = {}
 			signals.added[component] = listeners
 			local function on_add(entity, id, value)
 				for _, listener in listeners :: any do
 					listener(entity, id, value)
 				end
 			end
 			local existing_hook = world:get(component, jecs.OnAdd)
 			if existing_hook then
 				table.insert(listeners, existing_hook)
 			end
 			local idr = world.component_index[component]
 			if idr then
 				idr.hooks.on_add = on_add
 			else
 				world:set(component, jecs.OnAdd, on_add)
 			end
 		end
 		table.insert(listeners, fn)
 		return function()
 			local n = #listeners
 			local i = table.find(listeners, fn)
 			listeners[i] = listeners[n]
 			listeners[n] = nil
 		end
 	end
 	world_mut.changed = function<T>(
 		_: jecs.World,
 		component: jecs.Id<T>,
 		fn: (e: jecs.Entity, id: jecs.Id, value: T) -> ()
 	)
 		local listeners = signals.emplaced[component]
 		if not listeners then
 			listeners = {}
 			signals.emplaced[component] = listeners
 			local function on_change(entity, id, value: any)
 				for _, listener in listeners :: any do
 					listener(entity, id, value)
 				end
 			end
 			local existing_hook = world:get(component, jecs.OnChange)
 			if existing_hook then
 				table.insert(listeners, existing_hook)
 			end
 			local idr = world.component_index[component]
 			if idr then
 				idr.hooks.on_change = on_change
 			else
 				world:set(component, jecs.OnChange, on_change)
 			end
 		end
 		table.insert(listeners, fn)
 		return function()
 			local n = #listeners
 			local i = table.find(listeners, fn)
 			listeners[i] = listeners[n]
 			listeners[n] = nil
 		end
 	end
 	world_mut.removed = function<T>(
 		_: jecs.World,
 		component: jecs.Id<T>,
 		fn: (e: jecs.Entity, id: jecs.Id) -> ()
 	)
 		local listeners = signals.removed[component]
 		if not listeners then
 			listeners = {}
 			signals.removed[component] = listeners
 			local function on_remove(entity, id)
 				for _, listener in listeners :: any do
 					listener(entity, id)
 				end
 			end
 			local existing_hook = world:get(component, jecs.OnRemove)
 			if existing_hook then
 				table.insert(listeners, existing_hook)
 			end
 			local idr = world.component_index[component]
 			if idr then
 				idr.hooks.on_remove = on_remove
 			else
 				world:set(component, jecs.OnRemove, on_remove)
 			end
 		end
 		table.insert(listeners, fn)
 		return function()
 			local n = #listeners
 			local i = table.find(listeners, fn)
 			listeners[i] = listeners[n]
 			listeners[n] = nil
 		end
 	end
 	world_mut.signals = signals
 	world_mut.observer = observers_new
 	world_mut.monitor = monitors_new
 	world_mut.trackers = {}
 	return world_mut :: PatchedWorld
 end
 return observers_add
--- a/benches/visual/despawn.bench.luau
+++ b/benches/visual/despawn.bench.luau
@ -1,61 +1,65 @@
 --!optimize 2
 --!native
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
-local Matter = require(ReplicatedStorage.DevPackages.Matter)
+local jecs = require(ReplicatedStorage.Lib:Clone())
 local ecr = require(ReplicatedStorage.DevPackages.ecr)
 local jecs = require(ReplicatedStorage.Lib)
 local pair = jecs.pair
 local ecs = jecs.world()
-local mirror = require(ReplicatedStorage.mirror)
+local mirror = require(ReplicatedStorage.mirror:Clone())
-local mcs = mirror.World.new()
+local mcs = mirror.world()
 local C1 = ecs:component()
 local C2 = ecs:entity()
 ecs:add(C2, pair(jecs.OnDeleteTarget, jecs.Delete))
 local C3 = ecs:entity()
 ecs:add(C3, pair(jecs.OnDeleteTarget, jecs.Delete))
 local C4 = ecs:entity()
 ecs:add(C4, pair(jecs.OnDeleteTarget, jecs.Delete))
 local E1 = mcs:component()
 local E2 = mcs:entity()
 mcs:add(E2, pair(jecs.OnDeleteTarget, jecs.Delete))
 local E3 = mcs:entity()
 mcs:add(E3, pair(jecs.OnDeleteTarget, jecs.Delete))
 local E4 = mcs:entity()
-mcs:add(E4, pair(jecs.OnDeleteTarget, jecs.Delete))
+
 local m = mcs:entity()
 local j = ecs:entity()
 return {
 	ParameterGenerator = function()
 		local j = ecs:entity()
 		ecs:set(j, C1, true)
 		local m = mcs:entity()
 		mcs:set(m, E1, true)
 		for i = 1, 1000 do
 			local friend1 = ecs:entity()
 			local friend2 = mcs:entity()
 			ecs:add(friend1, pair(C2, j))
 			ecs:add(friend1, pair(C3, j))
 			ecs:add(friend1, pair(C4, j))
 			mcs:add(friend2, pair(E2, m))
 			mcs:add(friend2, pair(E3, m))
 			mcs:add(friend2, pair(E4, m))
 		end
 		return {
 			m = m,
 			j = j,
 		}
 	end,
 	Functions = {
-		Mirror = function(_, a)
+		Mirror = function()
-			mcs:delete(a.m)
+			for i = 1, 10 do
 				local friend2 = mcs:entity()
 				mcs:add(friend2, pair(E2, m))
 				mcs:add(friend2, pair(E3, m))
 				mcs:add(friend2, pair(E4, m))
 				-- local r = mirror.entity_index_try_get_fast(mcs.entity_index, friend2)
 				-- local archetype = r.archetype
 				-- mirror.archetype_destroy(mcs, archetype)
 				mcs:delete(m)
 				m = mcs:entity(m)
 			end
 		end,
-		Jecs = function(_, a)
+		Jecs = function()
-			ecs:delete(a.j)
+			for i = 1, 10 do
 				local friend1 = ecs:entity()
 				ecs:add(friend1, pair(C2, j))
 				ecs:add(friend1, pair(C3, j))
 				ecs:add(friend1, pair(C4, j))
 				-- local r = jecs.entity_index_try_get_fast(ecs.entity_index, friend1)
 				-- local archetype = r.archetype
 				-- jecs.archetype_destroy(ecs, archetype)
 				ecs:delete(j)
 				j = ecs:entity()
 			end
 		end,
 	},
 }
--- a/benches/visual/insertion.bench.luau
+++ b/benches/visual/insertion.bench.luau
@ -5,8 +5,7 @@ local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local jecs = require(ReplicatedStorage.Lib:Clone())
 local ecs = jecs.world()
 local mirror = require(ReplicatedStorage.mirror:Clone())
-local mcs = mirror.World.new()
+local mcs = mirror.world()
 local C1 = ecs:component()
 local C2 = ecs:component()
--- a/benches/visual/query.bench.luau
+++ b/benches/visual/query.bench.luau
@ -2,7 +2,7 @@
 --!native
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
-local Matter = require(ReplicatedStorage.DevPackages.matter)
+local Matter = require(ReplicatedStorage.DevPackages.Matter)
 local ecr = require(ReplicatedStorage.DevPackages.ecr)
 local newWorld = Matter.World.new()
--- a/benches/visual/remove.bench.luau
+++ b/benches/visual/remove.bench.luau
@ -4,15 +4,17 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local Matter = require(ReplicatedStorage.DevPackages.Matter)
 local ecr = require(ReplicatedStorage.DevPackages.ecr)
-local jecs = require(ReplicatedStorage.Lib)
+local jecs = require(ReplicatedStorage.Lib:Clone())
 local pair = jecs.pair
 local ecs = jecs.world()
-local mirror = require(ReplicatedStorage.mirror)
+local mirror = require(ReplicatedStorage.mirror:Clone())
-local mcs = mirror.World.new()
+local mcs = mirror.world()
 local C1 = ecs:component()
 local C2 = ecs:entity()
 ecs:add(C2, pair(jecs.OnDeleteTarget, jecs.Delete))
 ecs:add(C2, jecs.Exclusive)
 local C3 = ecs:entity()
 ecs:add(C3, pair(jecs.OnDeleteTarget, jecs.Delete))
 local C4 = ecs:entity()
@ -33,16 +35,17 @@ return {
 		Mirror = function()
 			local m = mcs:entity()
 			for i = 1, 100 do
-				mcs:add(m, E3)
+				mcs:add(m, pair(E2, E3))
-				mcs:remove(m, E3)
+				mcs:remove(m, pair(E2, E3))
 				mcs:add(m, pair(E2, E4))
 			end
 		end,
 		Jecs = function()
 			local j = ecs:entity()
 			for i = 1, 100 do
-				ecs:add(j, C3)
+				ecs:add(j, pair(C2, C3))
-				ecs:remove(j, C3)
+				ecs:add(j, pair(C2, C4))
 			end
 		end,
 	},
--- a/demo/src/ReplicatedStorage/collect.luau
+++ b/demo/src/ReplicatedStorage/collect.luau
@ -1,13 +1,11 @@
-local function collect<T...>(
+
-	signal: {
+--!strict
-		Connect: (RBXScriptSignal<T...>, fn: (T...) -> ()) -> RBXScriptConnection
+local function collect(signal)
 	}
 ): () -> (T...)
 	local enqueued = {}
 	local i = 0
-	local connection = (signal :: any):Connect(function(...)
+	local connection = signal:Connect(function(...)
 		table.insert(enqueued, { ... })
 		i += 1
 	end)
@ -25,4 +23,11 @@ local function collect<T...>(
 	end, connection
 end
-return collect
+type Signal<T... = ...any> = {
    Connect: (self: Signal<T...>, callback: (T...) -> ()) -> RBXScriptConnection,
    ConnectParallel: (self: Signal<T...>, callback: (T...) -> ()) -> RBXScriptConnection,
    Once: (self: Signal<T...>, callback: (T...) -> ()) -> RBXScriptConnection,
    Wait: (self: Signal<T...>) -> (T...)
 }
 return collect :: <T...>(Signal<T...>) -> (() -> (T...), RBXScriptConnection)
--- a/demo/src/ReplicatedStorage/components.luau
+++ b/demo/src/ReplicatedStorage/components.luau
@ -1,3 +1,5 @@
 --!strict
 local RunService = game:GetService("RunService")
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local jecs = require(ReplicatedStorage.ecs)
 local types = require("./types")
@ -5,31 +7,58 @@ local types = require("./types")
 local Networked = jecs.tag()
 local NetworkedPair = jecs.tag()
-local Renderable = jecs.component() :: jecs.Id<Instance>
+local InstanceMapping = jecs.component() :: jecs.Id<Instance>
-jecs.meta(Renderable, Networked)
+jecs.meta(InstanceMapping, jecs.OnAdd, function(component)
 	jecs.meta(component, jecs.OnAdd, function(entity, _, instance)
 		if RunService:IsServer() then
 			instance:SetAttribute("entity_server")
 		else
 			instance:SetAttribute("entity_client")
 		end
 	end)
 end)
 local function networked_id(ct)
 	jecs.meta(ct, Networked)
 	return ct
 end
 local function networked_pair(ct)
 	jecs.meta(ct, NetworkedPair)
 	return ct
 end
 local function instance_mapping_id(ct)
 	jecs.meta(ct, InstanceMapping)
 	return ct
 end
-local Poison = jecs.component() :: jecs.Id<number>
+local Renderable = jecs.component() :: types.Id<Instance>
-jecs.meta(Poison, Networked)
+local Poison = jecs.component() :: types.Id<number>
-
+local Health = jecs.component() :: types.Id<number>
-local Health = jecs.component() :: jecs.Id<number>
+local Player = jecs.component() :: types.Id<Player>
-jecs.meta(Health, Networked)
+local Debuff = jecs.tag() :: types.Entity
-
+local Lifetime = jecs.component() :: types.Id<{
-local Player = jecs.component() :: jecs.Id<Player>
+	duration: number,
-jecs.meta(Player, Networked)
+	created: number
-
+}>
 local Destroy = jecs.tag()
 local components = {
-	Renderable = Renderable,
+	Renderable = networked_id(instance_mapping_id(Renderable)),
-	Player = Player,
+	Player = networked_id(Player),
-	Poison = Poison,
+	Poison = networked_id(Poison),
-	Health = Health,
+	Health = networked_id(Health),
 	Lifetime = networked_id(Lifetime),
 	Debuff = networked_id(Debuff),
 	Destroy = networked_id(Destroy),
 	-- We have to define that some builtin IDs can also be networked
 	ChildOf = networked_pair(jecs.ChildOf),
 	Networked = Networked,
 	NetworkedPair = NetworkedPair,
 }
-for name, component in components do
+for name, component in components :: {[string]: types.Id<any> } do
 	jecs.meta(component, jecs.Name, name)
 end
--- a/demo/src/ReplicatedStorage/main.client.luau
+++ b/demo/src/ReplicatedStorage/main.client.luau
@ -1,13 +1,13 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local jecs = require(ReplicatedStorage.ecs)
 local schedule = require(ReplicatedStorage.schedule)
 local observers_add = require(ReplicatedStorage.observers_add)
 local SYSTEM = schedule.SYSTEM
 local RUN = schedule.RUN
 require(ReplicatedStorage.components)
-local world = observers_add(jecs.world())
+local world = jecs.world()
 local systems = ReplicatedStorage.systems
 SYSTEM(world, systems.receive_replication)
 SYSTEM(world, systems.entities_delete)
 RUN(world)
--- a/demo/src/ReplicatedStorage/observers_add.luau
+++ b/demo/src/ReplicatedStorage/observers_add.luau
@ -1,190 +0,0 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local jecs = require(ReplicatedStorage.ecs)
 type Observer<T...> = {
 	callback: (jecs.Entity) -> (),
 	query: jecs.Query<T...>,
 }
 export type PatchedWorld = jecs.World & {
 	added: <T>(PatchedWorld, jecs.Id<T>, (e: jecs.Entity, id: jecs.Id<T>, value: T) -> ()) -> (),
 	removed: (PatchedWorld, jecs.Id, (e: jecs.Entity, id: jecs.Id) -> ()) -> (),
 	changed: <T>(PatchedWorld, jecs.Id<T>, (e: jecs.Entity, id: jecs.Id<T>, value: T) -> ()) -> (),
 	-- deleted: (PatchedWorld, () -> ()) -> () -> (),
 	observer: (PatchedWorld, Observer<any>) -> (),
 	monitor: (PatchedWorld, Observer<any>) -> (),
 }
 local function observers_new(world, description)
 	local query = description.query
 	local callback = description.callback
 	local terms = query.filter_with :: { jecs.Id }
 	if not terms then
 		local ids = query.ids
 		query.filter_with = ids
 		terms = ids
 	end
 	local entity_index = world.entity_index :: any
 	local function emplaced(entity: jecs.Entity)
 		local r = jecs.entity_index_try_get_fast(
 			entity_index, entity :: any)
 		if not r then
 			return
 		end
 		local archetype = r.archetype
 		if jecs.query_match(query, archetype) then
 			callback(entity)
 		end
 	end
 	for _, term in terms do
 		world:added(term, emplaced)
 		world:changed(term, emplaced)
 	end
 end
 local function monitors_new(world, description)
 	local query = description.query
 	local callback = description.callback
 	local terms = query.filter_with :: { jecs.Id }
 	if not terms then
 		local ids = query.ids
 		query.filter_with = ids
 		terms = ids
 	end
 	local entity_index = world.entity_index :: any
 	local function emplaced(entity: jecs.Entity)
 		local r = jecs.entity_index_try_get_fast(
 			entity_index, entity :: any)
 		if not r then
 			return
 		end
 		local archetype = r.archetype
 		if jecs.query_match(query, archetype) then
 			callback(entity, jecs.OnAdd)
 		end
 	end
 	local function removed(entity: jecs.Entity, component: jecs.Id)
 		local r = jecs.entity_index_try_get_fast(
 			entity_index, entity :: any)
 		if not r then
 			return
 		end
 		local archetype = r.archetype
 		if jecs.query_match(query, archetype) then
 			callback(entity, jecs.OnRemove)
 		end
 	end
 	for _, term in terms do
 		world:added(term, emplaced)
 		world:removed(term, removed)
 	end
 end
 local function observers_add(world: jecs.World): PatchedWorld
 	local signals = {
 		added = {},
 		emplaced = {},
 		removed = {},
 		deleted = {}
 	}
 	world = world :: jecs.World & {[string]: any}
 	world.added = function(_, component, fn)
 		local listeners = signals.added[component]
 		if not listeners then
 			listeners = {}
 			signals.added[component] = listeners
 			local idr = jecs.id_record_ensure(world :: any, component :: any)
 			local rw = jecs.pair(component, jecs.Wildcard)
 			local idr_r = jecs.id_record_ensure(world :: any, rw :: any)
 			local function on_add(entity: number, id: number, value: any)
 				for _, listener in listeners do
 					listener(entity, id, value)
 				end
 			end
 			world:set(component, jecs.OnAdd, on_add)
 			idr.hooks.on_add = on_add :: any
 			idr_r.hooks.on_add = on_add :: any
 		end
 		table.insert(listeners, fn)
 	end
 	world.changed = function(_, component, fn)
 		local listeners = signals.emplaced[component]
 		if not listeners then
 			listeners = {}
 			signals.emplaced[component] = listeners
 			local idr = jecs.id_record_ensure(world :: any, component :: any)
 			local rw = jecs.pair(component, jecs.Wildcard)
 			local idr_r = jecs.id_record_ensure(world :: any, rw :: any)
 			local function on_change(entity: number, id: number, value: any)
 				for _, listener in listeners do
 					listener(entity, id, value)
 				end
 			end
 			world:set(component, jecs.OnChange, on_change)
 			idr.hooks.on_change = on_change :: any
 			idr_r.hooks.on_change = on_change :: any
 		end
 		table.insert(listeners, fn)
 	end
 	world.removed = function(_, component, fn)
 		local listeners = signals.removed[component]
 		if not listeners then
 			listeners = {}
 			signals.removed[component] = listeners
 			local idr = jecs.id_record_ensure(world :: any, component :: any)
 			local rw = jecs.pair(component, jecs.Wildcard)
 			local idr_r = jecs.id_record_ensure(world :: any, rw :: any)
 			local function on_remove(entity: number, id: number, value: any)
 				for _, listener in listeners do
 					listener(entity, id, value)
 				end
 			end
 			world:set(component, jecs.OnRemove, on_remove)
 			idr.hooks.on_remove = on_remove :: any
 			idr_r.hooks.on_remove = on_remove :: any
 		end
 		table.insert(listeners, fn)
 	end
 	world.signals = signals
 	world.observer = observers_new
 	world.monitor = monitors_new
 	-- local world_delete = world.delete
 	-- world.deleted = function(_, fn)
 	-- 	local listeners = signals.deleted
 	-- 	table.insert(listeners, fn)
 	-- end
 	-- world.delete = function(world, entity)
 	-- 	world_delete(world, entity)
 	-- 	for _, fn in signals.deleted do
 	-- 		fn(entity)
 	-- 	end
 	-- end
 	return world :: PatchedWorld
 end
 return observers_add
--- a/demo/src/ReplicatedStorage/remotes.luau
+++ b/demo/src/ReplicatedStorage/remotes.luau
@ -1,40 +1,32 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local types = require("../ReplicatedStorage/types")
 type Signal<T...> = {
 	Connect: (Signal<T...>, fn: (T...) -> ()) -> RBXScriptConnection
 }
 type Remote<T...> = {
-	FireClient: (Remote<T...>, T...) -> (),
+	FireClient: (Remote<T...>, Player, T...) -> (),
 	FireAllClients: (Remote<T...>, T...) -> (),
-	FireServer: (Remote<T...>) -> (),
+	FireServer: (Remote<T...>, T...) -> (),
-	OnServerEvent: {
+	OnServerEvent: RBXScriptSignal<(Player, T...)>,
-		Connect: (any, fn: (Player, T...) -> () ) -> ()
+	OnClientEvent: RBXScriptSignal<T...>
 	},
 	OnClientEvent: {
 		Connect: (any, fn: (T...) -> () ) -> ()
 	}
 }
-local function stream_ensure(name): Remote<any>
+local function stream_ensure(name)
 	local remote = ReplicatedStorage:FindFirstChild(name)
 	if not remote then
 		remote = Instance.new("RemoteEvent")
 		remote.Name = name
 		remote.Parent = ReplicatedStorage
 	end
-	return remote :: any
+	return remote
 end
-local function datagram_ensure(name): Remote<any>
+local function datagram_ensure(name)
 	local remote = ReplicatedStorage:FindFirstChild(name)
 	if not remote then
 		remote = Instance.new("UnreliableRemoteEvent")
 		remote.Name = name
 		remote.Parent = ReplicatedStorage
 	end
-	return remote :: any
+	return remote
 end
 return {
--- a/demo/src/ReplicatedStorage/systems/entities_delete.luau
+++ b/demo/src/ReplicatedStorage/systems/entities_delete.luau
@ -0,0 +1,13 @@
 --!strict
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local types = require(ReplicatedStorage.types)
 local ct = require(ReplicatedStorage.components)
 local function entities_delete(world: types.World, dt: number)
 	for e in world:each(ct.Destroy) do
 		world:delete(e)
 	end
 end
 return entities_delete
--- a/demo/src/ReplicatedStorage/systems/receive_replication.luau
+++ b/demo/src/ReplicatedStorage/systems/receive_replication.luau
@ -2,45 +2,51 @@ local types = require("../types")
 local jecs = require(game:GetService("ReplicatedStorage").ecs)
 local remotes = require("../remotes")
 local collect = require("../collect")
-local client_ids = {}
+local components = require("../components")
-local function ecs_map_get(world, id)
+local client_ids: {[jecs.Entity]: jecs.Entity } = {}
 	local deserialised_id = client_ids[id]
-	if not deserialised_id then
+local function ecs_ensure_entity(world: jecs.World, id: jecs.Entity)
-		if world:has(id, jecs.Name) then
+	local e = 0
-			deserialised_id = world:entity(id)
+
-		else
+	local ser_id = id
-			deserialised_id = world:entity()
+	local deser_id = client_ids[ser_id]
 	if deser_id  then
 		if deser_id == 0 then
 			local new_id = world:entity()
 			client_ids[ser_id] = new_id
 			deser_id = new_id
 		end
-
+	else
-		client_ids[id] = deserialised_id
+		if not world:exists(ser_id)
 			or (world:contains(ser_id) and not world:get(ser_id, jecs.Name))
 		then
 			deser_id = world:entity()
 		else
 			if world:contains(ser_id) and world:get(ser_id, jecs.Name) then
 				deser_id = ser_id
 			else
 				deser_id = world:entity()
 			end
 		end
 		client_ids[ser_id] = deser_id
 	end
-	-- local deserialised_id = client_ids[id]
+	e = deser_id
 	-- if not deserialised_id then
 	-- 	if world:has(id, jecs.Name) then
 	-- 		deserialised_id = world:entity(id)
 	-- 	else
 	-- 		if world:exists(id) then
 	-- 			deserialised_id = world:entity()
 	-- 		else
 	-- 			deserialised_id = world:entity(id)
 	-- 		end
 	-- 	end
 	-- 	client_ids[id] = deserialised_id
 	-- end
-	return deserialised_id
+	return e
 end
-local function ecs_make_alive_id(world, id)
+-- local rel_render = `e{jecs.ECS_ID(rel)}v{jecs.ECS_GENERATION(rel)}`
-	local rel = jecs.ECS_PAIR_FIRST(id)
+-- local tgt_render = `e{jecs.ECS_ID(tgt)}v{jecs.ECS_GENERATION(tgt)}`
-	local tgt = jecs.ECS_PAIR_SECOND(id)
+local function ecs_deser_pairs(world, token)
 	local tokens = string.split(token, ",")
 	local rel = tonumber(tokens[1])
 	local tgt = tonumber(tokens[2])
-	rel = ecs_map_get(world, rel)
+	rel = ecs_ensure_entity(world, rel)
-	tgt = ecs_map_get(world, tgt)
+	tgt = ecs_ensure_entity(world, tgt)
 	return jecs.pair(rel, tgt)
 end
@ -48,25 +54,31 @@ end
 local snapshots = collect(remotes.replication.OnClientEvent)
 return function(world: types.World)
 	for entity in world:each(components.Destroy) do
 		client_ids[entity] = nil
 	end
    for snapshot in snapshots do
-        for id, map in snapshot do
+        for ser_id, map in snapshot do
-        	id = tonumber(id)
+        	local id = tonumber(ser_id)
-            if jecs.IS_PAIR(id) then
+            if not id then
-            	id = ecs_make_alive_id(world, id)
+            	id = ecs_deser_pairs(world, ser_id)
            else
            	id = ecs_ensure_entity(world, id)
            end
            local set = map.set
            if set then
                if jecs.is_tag(world, id) then
                   	for _, entity in set do
-                       	entity = ecs_map_get(world, entity)
+                       	entity = ecs_ensure_entity(world, entity)
                  		world:add(entity, id)
                   	end
                else
                	local t = os.clock()
 	                local values = map.values
 	                for i, entity in set do
-						entity = ecs_map_get(world, entity)
+						entity = ecs_ensure_entity(world, entity)
-                  		world:set(entity, id, values[i])
+						world:set(entity, id, values[i])
                   	end
 			    end
            end
@ -74,11 +86,9 @@ return function(world: types.World)
            local removed = map.removed
            if removed then
-                for i, e in removed do
+                for _, entity in removed do
-                    if not world:contains(e) then
+                    entity = ecs_ensure_entity(world, entity)
-                        continue
+                    world:remove(entity, id)
                    end
                    world:remove(e, id)
                end
            end
        end
--- a/demo/src/ReplicatedStorage/types.luau
+++ b/demo/src/ReplicatedStorage/types.luau
@ -1,7 +1,6 @@
 local jecs = require(game:GetService("ReplicatedStorage").ecs)
 local observers_add = require("../ReplicatedStorage/observers_add")
-export type World = typeof(observers_add(jecs.world()))
+export type World = typeof(jecs.world())
 export type Entity = jecs.Entity
 export type Id<T> = jecs.Id<T>
 export type Snapshot = {
--- a/demo/src/ServerScriptService/main.server.luau
+++ b/demo/src/ServerScriptService/main.server.luau
@ -2,18 +2,20 @@ local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local ServerScriptService = game:GetService("ServerScriptService")
 local jecs = require(ReplicatedStorage.ecs)
 local schedule = require(ReplicatedStorage.schedule)
 local observers_add = require(ReplicatedStorage.observers_add)
 local SYSTEM = schedule.SYSTEM
 local RUN = schedule.RUN
 require(ReplicatedStorage.components)
-local world = observers_add(jecs.world())
+local world = jecs.world()
 local systems = ServerScriptService.systems
 SYSTEM(world, systems.replication)
 SYSTEM(world, systems.players_added)
 SYSTEM(world, systems.poison_hurts)
 SYSTEM(world, systems.health_regen)
 SYSTEM(world, systems.lifetimes_expire)
 SYSTEM(world, systems.life_is_painful)
 SYSTEM(world, ReplicatedStorage.systems.entities_delete)
 RUN(world, 0)
--- a/demo/src/ServerScriptService/systems/health_regen.luau
+++ b/demo/src/ServerScriptService/systems/health_regen.luau
@ -0,0 +1,15 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local ct = require(ReplicatedStorage.components)
 local types = require(ReplicatedStorage.types)
 return function(world: types.World, dt: number)
 	for e in world:query(ct.Player):without(ct.Health) do
 		world:set(e, ct.Health, 100)
 	end
 	for e, health in world:query(ct.Health) do
 		if math.random() < 1 / 60 / 30 then
 			world:set(e, ct.Health, 100)
 		end
 	end
 end
--- a/demo/src/ServerScriptService/systems/life_is_painful.luau
+++ b/demo/src/ServerScriptService/systems/life_is_painful.luau
@ -1,12 +1,19 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local ct = require(ReplicatedStorage.components)
 local types = require(ReplicatedStorage.types)
 local jecs = require(ReplicatedStorage.ecs)
 return function(world: types.World, dt: number)
-	for e in world:query(ct.Player):without(ct.Health) do
+	if math.random() < (1 / 60 / 7) then
-		world:set(e, ct.Health, 100)
+		for e in world:each(ct.Health) do
-	end
+			local poison = world:entity()
-	for e in world:query(ct.Player, ct.Health):without(ct.Poison) do
+			world:add(poison, ct.Debuff)
-		world:set(e, ct.Poison, 10)
+			world:add(poison, jecs.pair(jecs.ChildOf, e))
 			world:set(poison, ct.Poison, 10)
 			world:set(poison, ct.Lifetime, {
 				duration = 3,
 				created = os.clock()
 			})
 		end
 	end
 end
--- a/demo/src/ServerScriptService/systems/lifetimes_expire.luau
+++ b/demo/src/ServerScriptService/systems/lifetimes_expire.luau
@ -0,0 +1,12 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local ct = require(ReplicatedStorage.components)
 local types = require(ReplicatedStorage.types)
 return function(world: types.World, dt: number)
 	for e, lifetime in world:query(ct.Lifetime) do
 		if os.clock() > lifetime.created + lifetime.duration then
 			world:add(e, ct.Destroy)
 		end
 	end
 end
--- a/demo/src/ServerScriptService/systems/players_added.luau
+++ b/demo/src/ServerScriptService/systems/players_added.luau
@ -12,9 +12,13 @@ return function(world: types.World, dt: number)
 	for entity, player in world:query(ct.Player):without(ct.Renderable) do
 		local character = player.Character
-		if character then
+		if not character then
-		if not character.Parent then
+			continue
 			world:set(entity, ct.Renderable, character)
 		end
 		if not character.Parent then
 			continue
 		end
 		world:set(entity, ct.Renderable, character)
 	end
 end
--- a/demo/src/ServerScriptService/systems/poison_hurts.luau
+++ b/demo/src/ServerScriptService/systems/poison_hurts.luau
@ -1,12 +1,18 @@
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
 local ct = require(ReplicatedStorage.components)
-return function(world, dt)
+local types = require(ReplicatedStorage.types)
-	for e, poison, health in world:query(ct.Poison, ct.Health) do
+local jecs = require(ReplicatedStorage.ecs)
-		local health_after_tick = health - poison * dt * 0.05
+
-		if health_after_tick < 0 then
+return function(world: types.World, dt: number)
-			world:remove(e, ct.Health)
+	for e, poison_tick in world:query(ct.Poison, jecs.pair(jecs.ChildOf, jecs.w)) do
 		local tgt = world:target(e, jecs.ChildOf)
 		local health = world:get(tgt, ct.Health)
 		if not health then
 			continue
 		end
-		world:set(e, ct.Health, health_after_tick)
+
 		if math.random() < 1 / 60 / 1 and health > 1 then
 			world:set(tgt, ct.Health, health - 1)
 		end
 	end
 end
--- a/demo/src/ServerScriptService/systems/replication.luau
+++ b/demo/src/ServerScriptService/systems/replication.luau
@ -1,9 +1,12 @@
 --!strict
 local Players = game:GetService("Players")
 local ReplicatedStorage = game:GetService("ReplicatedStorage")
-local types = require("../../ReplicatedStorage/types")
+local ct = require(ReplicatedStorage.components)
-local ct = require("../../ReplicatedStorage/components")
+local components = ct :: { [string]: jecs.Entity }
 local remotes = require(ReplicatedStorage.remotes)
 local jecs = require(ReplicatedStorage.ecs)
-local remotes = require("../../ReplicatedStorage/remotes")
+local collect = require(ReplicatedStorage.collect)
-local components = ct :: {[string]: jecs.Entity }
+local ty = require(ReplicatedStorage.types)
 return function(world: ty.World)
@ -19,9 +22,10 @@ return function(world: ty.World)
    local networked_pairs = {}
    for component in world:each(ct.Networked) do
-    	local name = world:get(component, jecs.Name) :: string
+		local name = assert(world:get(component, jecs.Name), "Invalid component")
 		if components[name] == nil then
-			continue
+			error("Invalid component:"..name)
 		end
        storages[component] = {}
@ -32,29 +36,30 @@ return function(world: ty.World)
 	for relation in world:each(ct.NetworkedPair) do
 		local name = world:get(relation, jecs.Name) :: string
 		if not components[name] then
-			continue
+			error("Invalid component")
 		end
 		table.insert(networked_pairs, relation)
 	end
 	for _, component in networked_components do
-		local name = world:get(component, jecs.Name) :: string
+		local name = world:get(component, jecs.Name)
 		if not components[name] then
 			-- error("Invalid component")
 			error(`Networked Component (%id{component}%name{name})`)
 		end
 		local is_tag = jecs.is_tag(world, component)
 		local storage = storages[component]
 		if is_tag then
-		    world:added(component, function(entity)
+			world:added(component, function(entity)
-		        storage[entity] = true
+				storage[entity] = true
-		    end)
+			end)
 		else
-		    world:added(component, function(entity, _, value)
+			world:added(component, function(entity, _, value)
-		        storage[entity] = value
+				storage[entity] = value
-		    end)
+			end)
-		    world:changed(component, function(entity, _, value)
+			world:changed(component, function(entity, _, value)
-		        storage[entity] = value
+				storage[entity] = value
-		    end)
+			end)
 		end
        world:removed(component, function(entity)
@ -64,51 +69,55 @@ return function(world: ty.World)
 	for _, relation in networked_pairs do
 		world:added(relation, function(entity, id, value)
-	        local is_tag = jecs.is_tag(world, id)
+		local is_tag = jecs.is_tag(world, id)
-	        local storage = storages[id]
+		local storage = storages[id]
-	        if not storage then
+		if not storage then
-	            storage = {}
+			storage = {}
-	            storages[id] = storage
+			storages[id] = storage
-	        end
+		end
-	        if is_tag then
+		if is_tag then
-	            storage[entity] = true
+			storage[entity] = true
-	        else
+		else
-	            storage[entity] = value
+			storage[entity] = value
-	        end
+		end
-	    end)
+	end)
-	    world:changed(relation, function(entity, id, value)
+	world:changed(relation, function(entity, id, value)
-	        local is_tag = jecs.is_tag(world, id)
+		local is_tag = jecs.is_tag(world, id)
-	        if is_tag then
+		if is_tag then
-	            return
+			return
-	        end
+		end
-	        local storage = storages[id]
+		local storage = storages[id]
-	        if not storage then
+		if not storage then
-	            storage = {}
+			storage = {}
-	            storages[id] = storage
+			storages[id] = storage
-	        end
+		end
-	        storage[entity] = value
+		storage[entity] = value
-	    end)
+	end)
-	    world:removed(relation, function(entity, id)
+	world:removed(relation, function(entity, id)
-	        local storage = storages[id]
+		local storage = storages[id]
-	        if not storage then
+		if not storage then
-	            storage = {}
+			storage = {}
-	            storages[id] = storage
+			storages[id] = storage
-	        end
+		end
-	        storage[entity] = "jecs.Remove"
+		storage[entity] = "jecs.Remove"
-	    end)
+	end)
 	end
    -- local requested_snapshots = collect(remotes.request_snapshot.OnServerEvent)
    local players_added = collect(Players.PlayerAdded)
    return function()
        local snapshot_lazy: ty.Snapshot
        local set_ids_lazy: { jecs.Entity }
        -- In the future maybe it should be requested by the player instead when they
        -- are ready to receive the replication. Otherwise streaming could be complicated
        -- with intances references being nil.
 		for player in players_added do
 			if not snapshot_lazy then
 				snapshot_lazy, set_ids_lazy =  {}, {}
@ -126,7 +135,7 @@ return function(world: ty.World)
 						if is_tag then
 							set_values = table.create(entities_len, true)
 						else
-							local column = archetype.columns[archetype.records[component]]
+							local column = archetype.columns_map[component]
 							table.move(column, 1, entities_len, set_n + 1, set_values)
 						end
@ -135,10 +144,18 @@ return function(world: ty.World)
 					local set = table.move(set_ids_lazy, 1, set_n, 1, {})
-					snapshot_lazy[tostring(component)] = {
+					local ser_id: string = nil :: any
-					    set = if set_n > 0 then set else nil,
+
-					    values = if set_n > 0 then set_values else nil,
+					if jecs.IS_PAIR(component) then
-					}
+						ser_id = `{jecs.pair_first(world, component)},{jecs.pair_first(world, component)}`
 					else
 						ser_id = tostring(component)
 					end
 			    	snapshot_lazy[ser_id] = {
 	                    set = if set_n > 0 then set else nil,
 	                    values = if set_n > 0 then set_values else nil,
 	                }
 				end
 			end
@ -176,7 +193,15 @@ return function(world: ty.World)
            if dirty then
            	local removed = table.move(removed_ids, 1, removed_n, 1, {}) :: { jecs.Entity }
             	local set = table.move(set_ids, 1, set_n, 1, {}) :: { jecs.Entity }
-	            snapshot[tostring(component)] = {
+	            local ser_id: string = nil :: any
 				if jecs.IS_PAIR(component) then
 					ser_id = `{jecs.pair_first(world, component)},{jecs.pair_second(world, component)}`
 				else
 					ser_id = tostring(component)
 				end
 	            snapshot[ser_id] = {
                    set = if set_n > 0 then set else nil,
                    values = if set_n > 0 then set_values else nil,
                    removed = if removed_n > 0 then removed else nil
--- a/docs/api/jecs.md
+++ b/docs/api/jecs.md
@ -2,7 +2,7 @@
 Jecs. Just an Entity Component System.
-# Properties
+# Members
 ## World
 ```luau
@ -12,27 +12,93 @@ A world is a container of all ECS data. Games can have multiple worlds but compo
 ## Wildcard
 ```luau
-jecs.Wildcard: Entity
+jecs.Wildcard: Id
 ```
 Builtin component type. This ID is used for wildcard queries.
 ## Component
 ```luau
-jecs.Component: Entity
+jecs.Component: Id
 ```
 Builtin component type. Every ID created with [world:component()](world.md#component()) has this type added to it. This is meant for querying every component ID.
 ## ChildOf
 ```luau
-jecs.ChildOf: Entity
+jecs.ChildOf: Id
 ```
 Builtin component type. This ID is for creating parent-child hierarchies.
 ## OnAdd
 ```luau
 jecs.OnAdd: Id
 ```
 Builtin component type. This ID is for setting up a callback that is invoked when an instance of a component is added.
 ## OnRemove
 ```luau
 jecs.OnRemove: Id
 ```
 Builtin component type. This ID is for setting up a callback that is invoked when an instance of a component is removed.
 ## OnChange
 ```luau
 jecs.OnChange: Id
 ```
 Builtin component type. This ID is for setting up a callback that is invoked when an instance of a component is changed.
 ## Exclusive
 ```lua
 jecs.Exclusive: Id
 ```
 Builtin component type. This ID is for encoding that an ID is Exclusive meaning that an entity can never have more than one target for that exclusive relation.
 :::code-group
 ```luau [luau]
 local ChildOf = world:entity()
 world:add(ChildOf, jecs.Exclusive)
 local pop = world:entity()
 local dad = world:entity()
 local kid = world:entity()
 world:add(kid, pair(ChildOf, dad))
 print(world:target(kid, ChildOf, 0) == dad)
 world:add(kid, pair(ChildOf, pop))
 print(world:target(kid, ChildOf, 1) == dad) -- If ChildOf was not exclusive this would have been true
 print(world:target(kid, ChildOf, 0) == pop)
 -- Output:
 --  true
 --  false
 --  true
 ```
 :::info
 By default, jecs.ChildOf is already an exclusive relationship and this is just a demonstration of how to use it.
 In some cases you can use Exclusive relationships as a performance optimization as you can guarantee there will only be one target, therefore
 retrieving the data from a wildcard pair with that exclusive relationship can be deterministic.
 :::
 ## Name
 ```luau
 jecs.Name: Id
 ```
 Builtin component type. This ID is for naming components, but realistically you could use any component to do that.
 ## Rest
 ```luau
-jecs.Rest: Entity
+jecs.Rest: Id
 ```
 Builtin component type. This ID is simply for denoting the end of the range for builtin component IDs.
 # Functions
 ## pair()
@ -48,3 +114,30 @@ function jecs.pair(
 While relationship pairs can be used as components and have data associated with an ID, they cannot be used as entities. Meaning you cannot add components to a pair as the source of a binding.
 :::
 ## pair_first()
 ```luau
 function jecs.pair_first(
   	pair: Id, -- A full pair ID encoded using a relation-target pair.
 ): Entity -- The ID of the first element. Returns 0 if the ID is not alive.
 ```
 Returns the first element (the relation part) of a pair ID.
 **Example:**
 ```luau
 local Likes = world:component()
 local alice = world:entity()
 local bob = world:entity()
 local pair_id = pair(Likes, alice)
 local relation = jecs.pair_first(pair_id)
 print(relation == Likes) -- true
 ```
 ## pair_second()
 ```luau
 function jecs.pair_second(
   	pair: Id, -- A full pair ID encoded using a relation-target pair.
 ): Entity -- The ID of the second element. Returns 0 if the ID is not alive.
 ```
 Returns the second element (the target part) of a pair ID.
--- a/docs/api/observers.md
+++ b/docs/api/observers.md
@ -0,0 +1,196 @@
 # Observers
 The observers addon extends the World with signal-based reactivity and query-based observers. This addon provides a more ergonomic way to handle component lifecycle events and query changes.
 ## Installation
 The observers addon is included with jecs and can be imported directly:
 ```luau
 local jecs = require(path/to/jecs)
 local observers_add = require(path/to/jecs/addons/observers)
 local world = observers_add(jecs.world())
 ```
 ## Methods
 ### added
 Registers a callback that is invoked when a component is added to any entity.
 ```luau
 function World:added<T>(
    component: Id<T>,
    callback: (entity: Entity, id: Id<T>, value: T?) -> ()
 ): () -> () -- Returns an unsubscribe function
 ```
 **Parameters:**
 - `component` - The component ID to listen for additions
 - `callback` - Function called when component is added, receives entity, component ID, and value
 **Returns:** An unsubscribe function that removes the listener when called
 **Example:**
 ```luau
 local Health = world:component() :: jecs.Entity<number>
 local unsubscribe = world:added(Health, function(entity, id, value)
    print("Health component added to entity", entity, "with value", value)
 end)
 -- Later, to stop listening:
 unsubscribe()
 ```
 ### removed
 Registers a callback that is invoked when a component is removed from any entity.
 ```luau
 function World:removed<T>(
    component: Id<T>,
    callback: (entity: Entity, id: Id<T>) -> ()
 ): () -> () -- Returns an unsubscribe function
 ```
 **Parameters:**
 - `component` - The component ID to listen for removals
 - `callback` - Function called when component is removed, receives entity and component ID
 **Returns:** An unsubscribe function that removes the listener when called
 **Example:**
 ```luau
 local Health = world:component() :: jecs.Entity<number>
 local unsubscribe = world:removed(Health, function(entity, id)
    print("Health component removed from entity", entity)
 end)
 ```
 ### changed
 Registers a callback that is invoked when a component's value is changed on any entity.
 ```luau
 function World:changed<T>(
    component: Id<T>,
    callback: (entity: Entity, id: Id<T>, value: T) -> ()
 ): () -> () -- Returns an unsubscribe function
 ```
 **Parameters:**
 - `component` - The component ID to listen for changes
 - `callback` - Function called when component value changes, receives entity, component ID, and new value
 **Returns:** An unsubscribe function that removes the listener when called
 **Example:**
 ```luau
 local Health = world:component() :: jecs.Entity<number>
 local unsubscribe = world:changed(Health, function(entity, id, value)
    print("Health changed to", value, "for entity", entity)
 end)
 ```
 ### observer
 Creates a query-based observer that triggers when entities match or stop matching a query.
 ```luau
 function World:observer<T...>(
    query: Query<T...>,
    callback: ((entity: Entity, id: Id, value: any?) -> ())?
 ): () -> () -> Entity -- Returns an iterator function
 ```
 **Parameters:**
 - `query` - The query to observe for changes
 - `callback` - Optional function called when entities match the query
 **Returns:** An iterator function that returns entities that matched the query since last iteration
 **Example:**
 ```luau
 local Position = world:component() :: jecs.Id<Vector3>
 local Velocity = world:component() :: jecs.Id<Vector3>
 local moving_entities = world:observer(
    world:query(Position, Velocity),
    function(entity, id, value)
        print("Entity", entity, "started moving")
    end
 )
 -- In your game loop:
 for entity in moving_entities() do
    -- Process newly moving entities
 end
 ```
 ### monitor
 Creates a query-based monitor that triggers when entities are added to or removed from a query.
 ```luau
 function World:monitor<T...>(
    query: Query<T...>,
    callback: ((entity: Entity, id: Id, value: any?) -> ())?
 ): () -> () -> Entity -- Returns an iterator function
 ```
 **Parameters:**
 - `query` - The query to monitor for additions/removals
 - `callback` - Optional function called when entities are added or removed from the query
 **Returns:** An iterator function that returns entities that were added or removed since last iteration
 **Example:**
 ```luau
 local Health = world:component() :: jecs.Id<number>
 local health_changes = world:monitor(
    world:query(Health),
    function(entity, id, value)
        print("Health component changed for entity", entity)
    end
 )
 -- In your game loop:
 for entity in health_changes() do
    -- Process entities with health changes
 end
 ```
 ## Usage Patterns
 ### Component Lifecycle Tracking
 ```luau
 local Player = world:component()
 local Health = world:component() :: jecs.Id<number>
 -- Track when players are created
 world:added(Player, function(entity, id, instance)
 	instance:SetAttribute("entityid", entity)
 end)
 world:removed(Player, function(entity, id)
 	world:add(entity, Destroy) -- process its deletion later!
 end)
 ```
 ## Performance Considerations
 - **Signal listeners** are called immediately when components are added/removed/changed
 - **Query observers** cache the query for better performance
 - **Multiple listeners** for the same component are supported and called in registration order
 - **Unsubscribe functions** should be called when listeners are no longer needed to prevent memory leaks
 - **Observer iterators** should be called regularly to clear the internal buffer
 ## Integration with Built-in Hooks
 The observers addon integrates with the built-in component hooks (`OnAdd`, `OnRemove`, `OnChange`). If a component already has these hooks configured, the observers addon will preserve them and call both the original hook and any registered signal listeners.
--- a/docs/api/query.md
+++ b/docs/api/query.md
@ -4,13 +4,38 @@ A World contains entities which have components. The World is queryable and can
 # Methods
-## iter
+## cached
-Returns an iterator that can be used to iterate over the query.
+Returns a cached version of the query. This is useful if you want to create a query that you can iterate multiple times.
 ```luau
-function Query:iter(): () -> (Entity, ...)
+function Query:cached(): Query -- Returns the cached Query
 ```
 Example:
 ::: code-group
 ```luau [luau]
 local lerps = world:query(Lerp):cached() -- Ensure that you cache this outside a system so you do not create a new cache for a query every frame
 local function system(dt)
 	for entity, lerp in lerps do
 		-- Do something
 	end
 end
 ```
 ```ts [typescript]
 const lerps = world.query(Lerp).cached()
 function system(dt) {
 	for (const [entity, lerp] of lerps) {
 		// Do something
 	}
 }
 ```
 :::
 ## with
@ -83,15 +108,13 @@ Example:
 ```luau [luau]
 for i, archetype in world:query(Position, Velocity):archetypes() do
-    local columns = archetype.columns
+    local field = archetype.columns_map
-    local field = archetype.records
+    local positions = field[Position]
-
+    local velocities = field[Velocity]
    local P = field[Position]
    local V = field[Velocity]
    for row, entity in archetype.entities do
-        local position = columns[P][row]
+        local position = positions[row]
-        local velocity = columns[V][row]
+        local velocity = velocities[row]
        -- Do something
    end
 end
@ -101,10 +124,27 @@ end
 This function is meant for people who want to really customize their query behaviour at the archetype-level
 :::
-## cached
+## iter
-
+In most cases, you can iterate over queries directly using `for entity, ... in query do`. The `:iter()` method is mainly useful if you are on the old solver, to get types for the returned values.
 Returns a cached version of the query. This is useful if you want to iterate over the same query multiple times.
 ```luau
-function Query:cached(): Query -- Returns the cached Query
+function Query:iter(): () -> (Entity, ...)
 ```
 Example:
 ::: code-group
 ```luau [luau]
 local query = world:query(Position, Velocity)
 -- Direct iteration (recommended)
 for entity, position, velocity in query do
    -- Process entity
 end
 -- Using explicit iterator (when needed for the old solver)
 local iterator = query:iter()
 for entity, position, velocity in iterator do
    -- Process entity
 end
 ```
--- a/docs/api/world.md
+++ b/docs/api/world.md
@ -6,7 +6,7 @@ A World contains entities which have components. The World is queryable and can
 ## new
-`World` utilizes a class, meaning JECS allows you to create multiple worlds.
+`World` utilizes a class, meaning jecs allows you to create multiple worlds.
 ```luau
 function World.new(): World
@ -55,12 +55,12 @@ const entity = world.entity();
 ## component
-Creates a new component. Do note components are entities as well, meaning JECS allows you to add other components onto them.
+Creates a new component. Do note components are entities as well, meaning jecs allows you to add other components onto them.
 These are meant to be added onto other entities through `add` and `set`
 ```luau
-function World:component<T>(): Entity<T> -- The new componen.
+function World:component<T>(): Entity<T> -- The new component.
 ```
 Example:
@ -241,7 +241,10 @@ print(world.get(Entity, Health));
 // 100
 // 50
 ```
 :::
 :::info
 `world:set(entity, component, value)` propagates that a change has happened for thes component on this entity, while mutating a value directly would not.
 :::
 ## query
@ -289,10 +292,52 @@ If the index is larger than the total number of instances the entity has for the
 ```luau
 function World:target(
    entity: Entity, -- The entity
-    relation: Entity, -- The relationship between the entity and the target
+    relation: Id, -- The relationship between the entity and the target
    nth: number, -- The index
-): Entity? -- The target for the relationship at the specified index.
+): Id? -- The target for the relationship at the specified index.
 ```
 Example:
 ::: code-group
 ```luau [luau]
 local function timers_count(world: types.World)
 	local timers = world
 		:query(jecs.pair(ct.Timer, jecs.w))
 		:without(ct.Destroy)
 		:cached()
 	return function(_, dt: number)
 		for entity in timers do
 			local index = 0
 			local nth = world:target(entity, ct.Timer, index)
 			while nth do
 				local timer = world:get(entity, jecs.pair(ct.Timer, nth))
 				local elapsed = timer.elapsed + dt
 				if elapsed >= timer.duration then
 					world:add(entity, ct.Destroy)
 				end
 				timer.elapsed = elapsed
 			end
 		end
 	end
 end
 ```
 ```ts [typescript]
 const entity = world.entity();
 print(world.contains(entity));
 print(world.contains(1));
 print(world.contains(2));
 // Outputs:
 // true
 // true
 // false
 ```
 :::
 ## parent
@ -355,9 +400,9 @@ print(world.contains(2));
 Removes a component (ID) from an entity
 ```luau
-function World:remove(
+function World:remove<T>(
    entity: Entity,
-	component: Entity<T>
+	component: Id<T>
 ): void
 ```
@ -458,20 +503,20 @@ Useful when you only need the entity for a specific ID and you want to avoid cre
 ```luau
 function World:each(
-	id: Entity -- The component ID
+	component: Id -- The component ID
 ): () -> Entity
 ```
 Example:
 ::: code-group
 ```luau [luau]
-local id = world:entity()
+local id = world:component()
 for entity in world:each(id) do
 	-- Do something
 end
 ```
 ```ts [typescript]
-const id = world.entity();
+const id = world.component();
 for (const entity of world.each(id)) {
 	// Do something
 }
@ -500,6 +545,122 @@ Enforces a check for entities to be created within a desired range.
 ```luau
 function World:range(
 	range_begin: number -- The starting point,
-	range_begin: number? -- The end point (optional)
+	range_end: number? -- The end point (optional)
 )
 ```
 Example:
 ::: code-group
 ```luau [luau]
 world:range(1000, 5000) -- Entities will be created with IDs 1000-5000
 local entity = world:entity()
 print(entity) -- Will be >= 1000 and < 5000
 ```
 ```ts [typescript]
 world.range(1000, 5000) // Entities will be created with IDs 1000-5000
 const entity = world.entity()
 print(entity) // Will be >= 1000 and < 5000
 ```
 :::
 ## parent
 Gets the parent entity of the specified entity using the built-in `ChildOf` relationship.
 ```luau
 function World:parent(
    entity: Entity
 ): Entity? -- Returns the parent entity or nil if no parent
 ```
 Example:
 ::: code-group
 ```luau [luau]
 local parent = world:entity()
 local child = world:entity()
 world:add(child, pair(jecs.ChildOf, parent))
 local retrieved_parent = world:parent(child)
 print(retrieved_parent == parent) -- true
 ```
 ```ts [typescript]
 const parent = world.entity()
 const child = world.entity()
 world.add(child, pair(jecs.ChildOf, parent))
 const retrievedParent = world.parent(child)
 print(retrievedParent === parent) // true
 ```
 :::
 ## contains
 Checks if an entity exists and is alive in the world.
 ```luau
 function World:contains(
    entity: Entity
 ): boolean
 ```
 Example:
 ::: code-group
 ```luau [luau]
 local entity = world:entity()
 print(world:contains(entity)) -- true
 world:delete(entity)
 print(world:contains(entity)) -- false
 ```
 ```ts [typescript]
 const entity = world.entity()
 print(world.contains(entity)) // true
 world.delete(entity)
 print(world.contains(entity)) // false
 ```
 :::
 ## exists
 Checks if the entity ID exists regardless of whether it is alive or not. Useful to know if the ID is occupied in the entity index.
 ```luau
 function World:exists(
    entity: Entity
 ): boolean
 ```
 ## cleanup
 Cleans up deleted entities and their associated data. This is automatically called by jecs, but can be called manually if needed.
 ```luau
 function World:cleanup(): void
 ```
 Example:
 ::: code-group
 ```luau [luau]
 local entity = world:entity()
 world:delete(entity)
 -- Cleanup is usually automatic, but can be called manually
 world:cleanup()
 ```
 ```ts [typescript]
 const entity = world.entity()
 world.delete(entity)
 // Cleanup is usually automatic, but can be called manually
 world.cleanup()
 ```
 :::
--- a/docs/learn/overview.md
+++ b/docs/learn/overview.md
@ -27,8 +27,8 @@ local jecs = require(path/to/jecs)
 local world = jecs.world()
 ```
 ```typescript [typescript]
-import { World } from "@rbxts/jecs"
+import * as jecs from "@rbxts/jecs"
-const world = new World()
+const world = jecs.world()
 // creates a new entity with no components and returns its identifier
 const entity = world.entity()
@ -156,6 +156,13 @@ world.set(Transform, OnChange, (entity, id, data) => {
 ```
 :::
 :::info
 Children are cleaned up before parents
 When a parent and its children are deleted, OnRemove hooks will be invoked for children first, under the condition that there are no cycles in the relationship graph of the deleted entities. This order is maintained for any relationship that has the (OnDeleteTarget, Delete) trait (see Component Traits for more details).
 When an entity graph contains cycles, order is undefined. This includes cycles that can be formed using different relationships.
 :::
 ### Cleanup Traits
 When entities that are used as tags, components, relationships or relationship targets are deleted, cleanup traits ensure that the store does not contain any dangling references. Any cleanup policy provides this guarantee, so while they are configurable, games cannot configure traits that allows for dangling references.
@ -166,15 +173,22 @@ This is what cleanup traits are for: to specify which action needs to be execute
 To configure a cleanup policy for an entity, a `(Condition, Action)` pair can be added to it. If no policy is specified, the default cleanup action (`Remove`) is performed.
-There are two cleanup actions:
+#### Cleanup Traits Summary
-   `Remove`: removes instances of the specified (component) id from all entities (default)
+| Condition | Action | Description | Use Case |
-   `Delete`: deletes all entities with specified id
+|-----------|--------|-------------|----------|
 | `OnDelete` | `Remove` | Removes the component from all entities when the component is deleted | Default behavior, safe cleanup |
 | `OnDelete` | `Delete` | Deletes all entities that have the component when the component is deleted | Cascading deletion, dangerous |
 | `OnDeleteTarget` | `Remove` | Removes the relationship from all entities when the target is deleted | Safe relationship cleanup |
 | `OnDeleteTarget` | `Delete` | Deletes all entities that have the relationship when the target is deleted | Hierarchical deletion (e.g., parent-child) |
-There are two cleanup conditions:
+**Cleanup Actions:**
 - `Remove`: removes instances of the specified (component) id from all entities (default)
 - `Delete`: deletes all entities with specified id
-   `OnDelete`: the component, tag or relationship is deleted
+**Cleanup Conditions:**
-   `OnDeleteTarget`: a target used with the relationship is deleted
+- `OnDelete`: the component, tag or relationship is deleted
 - `OnDeleteTarget`: a target used with the relationship is deleted
 #### (OnDelete, Remove)
 ::: code-group
@ -285,9 +299,10 @@ jecs.world() -- Position gets registered here
 ```
 ```typescript [typescript]
 import { world } from "@rbxts/jecs"
 const Position = jecs.component<Vector3>();
-new World() // Position gets registered here
+world() // Position gets registered here
 ```
 :::
@ -301,9 +316,11 @@ jecs.world() -- Position gets registered here with its name "Position"
 ```
 ```typescript [typescript]
 import { world } from "@rbxts/jecs"
 jecs.meta(Position, jecs.Name, "Position")
-new World() // Position gets registered here with its name "Position"
+world() // Position gets registered here with its name "Position"
 ```
 :::
@ -632,7 +649,7 @@ world:set(e, pair(Eats, Apples), { amount = 1 })
 world:set(e, pair(Begin, Position), Vector3.new(0, 0, 0))
 world:set(e, pair(End, Position), Vector3.new(10, 20, 30))
-world:add(e, jecs.ChildOf, Position)
+world:add(e, pair(jecs.ChildOf, Position))
 ```
 ```typescript [typescript]
@ -648,7 +665,7 @@ world.set(e, pair(Eats, Apples), { amount: 1 })
 world.set(e, pair(Begin, Position), new Vector3(0, 0, 0))
 world.set(e, pair(End, Position), new Vector3(10, 20, 30))
-world.add(e, jecs.ChildOf, Position)
+world.add(e, pair(jecs.ChildOf, Position))
 ```
 :::
@ -695,3 +712,7 @@ To improve the speed of evaluating queries, Jecs has indices that store all arch
 While registering an archetype for a relationship index is not more expensive than registering an archetype for a regular index, an archetype with relationships has to also register itself with the appropriate wildcard indices for its relationships. For example, an archetype with relationship `pair(Likes, Apples)` registers itself with the `pair(Likes, Apples)`, `pair(Likes, jecs.Wildcard)` and `pair(jecs.Wildcard, Apples)` indices. For this reason, creating new archetypes with relationships has a higher overhead than an archetype without relationships.
 This page takes wording and terminology directly from Flecs, the first ECS with full support for [Entity Relationships](https://www.flecs.dev/flecs/md_docs_2Relationships.html).
 ## Next Steps
 - [API Reference](../api/jecs.md) - Complete API documentation
--- a/docs/resources.md
+++ b/docs/resources.md
@ -49,8 +49,8 @@ A tool for inspecting entity lifetimes
 ### Helpers
-#### [jecs_observers](https://github.com/Ukendio/jecs/blob/main/addons/observers.luau)
+#### [jecs_ob](https://github.com/Ukendio/jecs/blob/main/addons/ob.luau)
-Observers for queries and signals for components
+Observers & Monitors for queries
 ### [hammer](https://github.com/Mark-Marks/hammer)
 A set of utilities for Jecs
--- a/jecs.d.ts
+++ b/jecs.d.ts
@ -49,7 +49,7 @@ export type Archetype<T extends unknown[]> = {
 	type: string;
 	entities: number[];
 	columns: Column<unknown>[];
-	columns_map: { [K in keyof T]: Column<T[K]> }
+	columns_map: Record<Id, Column<T[number]>>
 };
 type Iter<T extends unknown[]> = IterableFunction<LuaTuple<[Entity, ...T]>>;
@ -105,7 +105,7 @@ export class World {
 	/**
 	 * Creates a new World.
 	 */
-	constructor();
+	private constructor();
 	/**
 	 * Enforces a check for entities to be created within a desired range.
@ -156,8 +156,8 @@ export class World {
 	 * @param hook The hook to install.
 	 * @param value The hook callback.
 	 */
-	set<T>(component: Entity<T>, hook: StatefulHook, value: (e: Entity<T>, id: Id<T>, data: T) => void): void;
+	set<T>(component: Entity<T>, hook: StatefulHook, value: (e: Entity, id: Id<T>, data: T) => void): void;
-	set<T>(component: Entity<T>, hook: StatelessHook, value: (e: Entity<T>, id: Id<T>) => void): void;
+	set<T>(component: Entity<T>, hook: StatelessHook, value: (e: Entity, id: Id<T>) => void): void;
 	/**
 	 * Assigns a value to a component on the given entity.
 	 * @param entity The target entity.
@ -247,8 +247,14 @@ export class World {
 	 * @returns A Query object to iterate over results.
 	 */
 	query<T extends Id[]>(...components: T): Query<InferComponents<T>>;
 	added<T>(component: Entity<T>, listener: (e: Entity, id: Id<T>, value: T) => void): () => void
 	changed<T>(component: Entity<T>, listener: (e: Entity, id: Id<T>, value: T) => void): () => void
 	removed<T>(component: Entity<T>, listener: (e: Entity, id: Id<T>) => void): () => void
 }
 export function world(): World;
 export function component<T>(): Entity<T>;
 export function tag(): Tag;
@ -301,6 +307,7 @@ export declare const OnAdd: StatefulHook;
 export declare const OnRemove: StatelessHook;
 export declare const OnChange: StatefulHook;
 export declare const ChildOf: Tag;
 export declare const Component: Tag;
 export declare const Wildcard: Entity;
 export declare const w: Entity;
 export declare const OnDelete: Tag;
@ -308,6 +315,7 @@ export declare const OnDeleteTarget: Tag;
 export declare const Delete: Tag;
 export declare const Remove: Tag;
 export declare const Name: Entity<string>;
 export declare const Exclusive: Tag;
 export declare const Rest: Entity;
 export type ComponentRecord = {
@ -317,3 +325,6 @@ export type ComponentRecord = {
 }
 export function component_record(world: World, id: Id): ComponentRecord
 export function bulk_insert<const C extends Id[]>(world: World, entity: Entity, ids: C, values: InferComponents<C>): void
 export function bulk_remove(world: World, entity: Entity, ids: Id[]): void
--- a/jecs.luau
+++ b/jecs.luau
--- a/mirror.luau
+++ b/mirror.luau
--- a/package.json
+++ b/package.json
@ -1,6 +1,6 @@
 {
 	"name": "@rbxts/jecs",
-	"version": "0.7.2",
+	"version": "0.9.0-rc.8",
 	"description": "Stupidly fast Entity Component System",
 	"main": "jecs.luau",
 	"repository": {
--- a/test/addons/observers.luau
+++ b/test/addons/observers.luau
@ -2,43 +2,28 @@ local jecs = require("@jecs")
 local testkit = require("@testkit")
 local test = testkit.test()
 local CASE, TEST, FINISH, CHECK = test.CASE, test.TEST, test.FINISH, test.CHECK
-local observers_add = require("@addons/observers")
+local FOCUS = test.FOCUS
 local ob = require("@addons/ob")
 TEST("addons/observers", function()
 	local world = observers_add(jecs.world())
-	do CASE "Should work even if set after the component has been used"
+	local world = jecs.world()
 	do CASE "monitors should accept pairs"
 		local A = world:component()
 		local B = world:component()
-		world:set(world:entity(), A, 2)
+		local c = 1
-		local ran = false
+		ob.monitor(world:query(jecs.pair(A, B)), function (_, event)
-		world:added(A, function()
+			c += 1
 			ran = true
 		end)
-		local entity = world:entity()
+		local child = world:entity()
-		world:set(entity, A, 3)
+		world:add(child, jecs.pair(A, B))
 		CHECK(c == 2)
-		CHECK(ran)
+		world:remove(child, jecs.pair(A, B))
 		CHECK(c == 3)
 	end
 	do CASE "Should not override hook"
 		local A = world:component()
 		local count = 1
 		local function counter()
 			count += 1
 		end
 		world:set(A, jecs.OnAdd, counter)
 		world:added(A, counter)
 		world:set(world:entity(), A, false)
 		CHECK(count == (1 + 2))
 		world:set(world:entity(), A, false)
 		CHECK(count == (1 + (2 * 2)))
 	end
 	do CASE "Ensure ordering between signals and observers"
 		local A = world:component()
 		local B = world:component()
@ -48,11 +33,15 @@ TEST("addons/observers", function()
 			count += 1
 		end
-		world:observer(world:query(A, B), counter)
+		ob.observer(world:query(A, B), counter)
 		world:added(A, counter)
 		world:added(A, counter)
 		for _ in world:query(A) do
 		end
 		local e = world:entity()
 		world:add(e, A)
 		CHECK(count == 3)
@ -69,7 +58,7 @@ TEST("addons/observers", function()
 			count += 1
 		end
-		world:observer(world:query(A), counter)
+		ob.observer(world:query(A), counter)
 		local e = world:entity()
 		world:set(e, A, false)
@ -89,7 +78,7 @@ TEST("addons/observers", function()
 			count += 1
 		end
-		world:monitor(world:query(A), counter)
+		ob.monitor(world:query(A), counter)
 		local e = world:entity()
 		world:set(e, A, false)
--- a/test/tests.luau
+++ b/test/tests.luau
@ -22,9 +22,185 @@ type Entity<T=nil> = jecs.Entity<T>
 type Id<T=unknown> = jecs.Id<T>
 local entity_visualiser = require("@tools/entity_visualiser")
 local lifetime_tracker_add = require("@tools/lifetime_tracker")
 local dwi = entity_visualiser.stringify
 TEST("ardi", function()
 	local world = jecs.world()
 	local r = world:entity()
 	world:add(r, jecs.pair(jecs.OnDelete, jecs.Delete))
 	local e = world:entity()
 	local e1 = world:entity()
 	world:add(e, jecs.pair(r, e1))
 	world:delete(r)
 	CHECK(not world:contains(e))
 end)
 TEST("dai", function()
 	local world = jecs.world()
 	local C = world:component()
 	world:set(C, jecs.Name, "C")
 	CHECK(world:get(C, jecs.Name) == "C")
 	world:entity(2000)
 	CHECK(world:get(C, jecs.Name) == "C")
 end)
 TEST("another axen banger", function()
 	-- taken from jecs.luau
 	local world = jecs.world()
 	world:range(2000, 3000)
 	local e0v1_id = jecs.ECS_COMBINE(1000, 1) -- id can be both within or outside the world's range
 	local e0v1 = world:entity(e0v1_id)
 	assert(world:contains(e0v1)) -- fails
 end)
 TEST("Ensure archetype edges get cleaned", function()
 	local A = jecs.component()
 	local B = jecs.component()
 	local world = jecs.world()
 	local edges = world.archetype_edges
 	local e = world:entity()
 	local r = jecs.record(world, e)
 	world:set(e, A, true)
 	world:add(e, A)
 	local arch_a = r.archetype
 	world:set(e, B, true)
 	world:add(e, B)
 	local arch_ab = r.archetype
 	CHECK(edges[arch_a.id][B] == arch_ab)
 	CHECK(edges[arch_ab.id][B] == arch_a)
 	world:delete(B)
 	CHECK(edges[arch_a.id][B] == nil)
 	CHECK(edges[arch_ab.id][A] == nil)
 	for _ in edges[arch_ab.id] do
 		CHECK(false)
 	end
 	world:delete(A)
 	CHECK(edges[arch_a.id][B] == nil)
 	CHECK(edges[arch_a.id][A] == nil)
 	for _ in edges[arch_a.id] do
 		CHECK(false)
 	end
 end)
 TEST("repeated entity cached query", function()
 	local pair = jecs.pair
 	local world = jecs.world()
 	local rel = world:entity()
 	local cmp = world:component()
 	local query = world:query(cmp):cached()
 	local t1 = world:entity()
 	local p1 = pair(rel, t1)
 	local e1 = world:entity()
 	world:add(e1, p1)
 	world:set(e1, cmp, true)
 	CHECK(query:iter()() == e1)
 	world:delete(e1)
 	world:delete(t1)
 	local t2 = world:entity()
 	local p2 = pair(rel, t2)
 	local e2 = world:entity()
 	world:add(e2, p2)
 	world:set(e2, cmp, true)
 	CHECK(query:iter()() == e2) -- Fails
 end)
 TEST("repeated pairs", function()
 	local pair = jecs.pair
 	local world = jecs.world()
 	local rel = world:component() -- Does not error if this is just a tag
 	-- Does not happen if we delete manually instead of using this
 	world:add(rel, pair(jecs.OnDeleteTarget, jecs.Delete))
 	local t1 = world:entity()
 	local p1 = pair(rel, t1)
 	local e1 = world:entity()
 	world:set(e1, p1, true)
 	CHECK(world:get(e1, p1))
 	CHECK(world:each(p1)() == e1)
 	world:delete(t1)
 	local t2 = world:entity()
 	local p2 = pair(rel, t2)
 	local e2 = world:entity()
 	print("-----")
 	world:set(e2, p2, true)
 	CHECK(world:get(e2, p2))
 	CHECK(p1 == p2)
 	local count = 0
 	CHECK(world:has(e2, p2))
 	for _ in world:query(p2) do
 		count += 1
 	end
 	CHECK(count == 1)
 	CHECK(world:each(p2)() == e2) -- Fails
 end)
 TEST("repro", function()
 	local world = jecs.world()
 	local data = world:component()
 	local relation = world:component()
 	world:add(relation, jecs.pair(jecs.OnDeleteTarget, jecs.Delete))
 	local e1 = world:entity()
 	local e2 = world:entity()
 	world:set(e2, data, 456)
 	world:add(e2, jecs.pair(relation, e1))
 	world:delete(e1)
 	local e1v1 = world:entity()
 	CHECK(ECS_ID(e1v1) == e1::any)
 	local e2v1 = world:entity()
 	CHECK(ECS_ID(e2v1) == e2::any)
 	world:set(e2v1, data, 456)
 	CHECK(world:contains(e1v1))
 	CHECK(not world:contains(e2))
 	CHECK(world:contains(e2v1))
 	local count = 0
 	for i,val in world:query(data):iter() do
 		count += 1
 	end
 	CHECK(count == 1)
 	count = 0
 	print("----")
 	world:add(e2v1, jecs.pair(relation, e1v1))
 	CHECK(world:has(e2v1, jecs.pair(relation, e1v1)))
 	for i,val in world:query(data):iter() do
 		count += 1
 	end
 	print(count)
 	CHECK(count==1)
 end)
 TEST("bulk", function()
 	local world = jecs.world()
 	local A = world:component()
@ -42,7 +218,10 @@ TEST("bulk", function()
 	CHECK(world:get(e, B) == 2)
 	CHECK(world:get(e, C) == 3)
-	jecs.bulk_insert(world, e, { D, E, F }, { 4, nil, 5 })
+	jecs.bulk_insert(world, e,
 		{ D, E, F },
 		{ 4, nil, 5 }
 	)
 	CHECK(world:get(e, A) == 1)
 	CHECK(world:get(e, B) == 2)
 	CHECK(world:get(e, C) == 3)
@ -51,7 +230,10 @@ TEST("bulk", function()
 	CHECK(world:get(e, E) == nil and world:has(e, E))
 	CHECK(world:get(e, F) == 5)
-	jecs.bulk_insert(world, e, { A, D, E, F, C }, { 10, 40, nil, 50, 30 })
+	jecs.bulk_insert(world, e,
 		{ A, D, E, F, C },
 		{ 10, 40, nil, 50, 30 }
 	)
 	CHECK(world:get(e, A) == 10)
 	CHECK(world:get(e, B) == 2)
@ -137,6 +319,66 @@ TEST("repro", function()
 end)
 TEST("world:add()", function()
 	do CASE "exclusive relations"
 		local world = jecs.world()
 		local A = world:component()
 		world:add(A, jecs.Exclusive)
 		local B = world:component()
 		local C = world:component()
 		local e = world:entity()
 		world:add(e, pair(A, B))
 		world:add(e, pair(A, C))
 		CHECK(world:has(e, pair(A, B)) == false)
 		CHECK(world:has(e, pair(A, C)) == true)
 	end
 	do CASE "exclusive relations invoke hooks"
 		local world = jecs.world()
 		local A = world:component()
 		local B = world:component()
 		local C = world:component()
 		local e_ptr: jecs.Entity = (jecs.Rest :: any) + 1
 		world:add(A, jecs.Exclusive)
 		local on_remove_call = false
 		world:set(A, jecs.OnRemove, function(e, id)
 			on_remove_call = true
 		end)
 		local on_add_call_count = 0
 		world:set(A, jecs.OnAdd, function(e, id)
 			on_add_call_count += 1
 		end)
 		local e = world:entity()
 		CHECK(e == e_ptr)
 		world:add(e, pair(A, B))
 		CHECK(on_add_call_count == 1)
 		world:add(e, pair(A, C))
 		CHECK(on_add_call_count == 2)
 		CHECK(on_remove_call)
 		CHECK(world:has(e, pair(A, B)) == false)
 		CHECK(world:has(e, pair(A, C)) == true)
 		-- We have to ensure that it actually invokes hooks everytime it
 		-- traverses the archetype
 		e = world:entity()
 		world:add(e, pair(A, B))
 		CHECK(on_add_call_count == 3)
 		world:add(e, pair(A, C))
 		CHECK(on_add_call_count == 4)
 		CHECK(on_remove_call)
 		CHECK(world:has(e, pair(A, B)) == false)
 		CHECK(world:has(e, pair(A, C)) == true)
 	end
 	do CASE "idempotent"
 		local world = jecs.world()
 		local d = dwi(world)
@ -188,6 +430,9 @@ TEST("world:children()", function()
 	local e3 = world:entity()
 	world:add(e3, pair(ChildOf, e1))
 	CHECK(world:has(e2, pair(ChildOf, e1)))
 	CHECK(world:has(e3, pair(ChildOf, e1)))
 	local count = 0
 	for entity in world:children(e1) do
 		count += 1
@ -376,8 +621,51 @@ TEST("world:contains()", function()
 end)
 TEST("world:delete()", function()
 	do CASE "pair(OnDelete, Delete)"
 	    local world = jecs.world()
 	    local ct = world:component()
 	    world:add(ct, jecs.pair(jecs.OnDelete, jecs.Delete))
 	    local e1 = world:entity()
 	    local e2 = world:entity()
 	    local dummy = world:entity()
 	    world:add(e1, ct)
 	    world:add(e2, jecs.pair(ct, dummy))
 	    -- world:delete(dummy)
 	    -- CHECK(world:contains(e2))
 	    world:delete(ct)
 	    CHECK(not world:contains(e1))
 	end
 	do CASE "pair(OnDeleteTarget, Delete)"
 	    local world = jecs.world()
 	    local ct = world:component()
 	    world:add(ct, jecs.pair(jecs.OnDeleteTarget, jecs.Delete))
 	    local e1 = world:entity()
 	    local e2 = world:entity()
 	    local dummy = world:entity()
 	    world:add(e1, ct)
 	    world:add(e2, jecs.pair(ct, dummy))
 	    world:delete(dummy)
 	    CHECK(not world:contains(e2))
 	    world:delete(ct)
 	    CHECK(world:contains(e1))
 	end
 	do CASE "remove (*, R) pairs when relationship is invalidated"
 		print("-------")
 		local world = jecs.world()
 		local e1 = world:entity()
 		local e2 = world:entity()
@ -441,7 +729,7 @@ TEST("world:delete()", function()
 		local A = world:entity()
 		local B = world:entity()
-		world:add(Relation, pair(jecs.OnDelete, jecs.Delete))
+		world:add(Relation, pair(jecs.OnDeleteTarget, jecs.Delete))
 		local entity = world:entity()
@ -548,7 +836,6 @@ TEST("world:delete()", function()
 		CHECK(not world:has(id1, Health))
 	end
 	do CASE "delete children"
 		local world = jecs.world()
@ -735,6 +1022,16 @@ TEST("world:delete()", function()
 		CHECK(not world:contains(bob))
 		CHECK(not world:contains(alice))
 	end
 	do CASE "deleted entity should not be able to be operated on"
 		local world = jecs.world()
 		local e = world:entity()
 		local A = world:component()
 		world:set(e, A, true)
 		world:delete(e)
 		world:set(e, A, true)
 		CHECK(world:has(e, A) == false)
 	end
 end)
 TEST("world:each()", function()
@ -765,19 +1062,180 @@ TEST("world:each()", function()
 	end
 end)
 TEST("world:added", function()
 	local world = jecs.world()
 	do CASE "Should work even if set after the component has been used"
 		local A = world:component()
 		world:set(world:entity(), A, 2)
 		local ran = false
 		world:added(A, function()
 			ran = true
 		end)
 		local entity = world:entity()
 		world:set(entity, A, 3)
 		CHECK(ran)
 	end
 	do CASE "Should work even if set after the pair has been used"
 		local A = world:component()
 		local B = world:component()
 		world:set(world:entity(), A, 2)
 		world:set(world:entity(), pair(A, B), 2)
 		world:added(A, function()
 			ran = true
 		end)
 		local entity = world:entity()
 		world:set(entity, pair(A, B), 3)
 		CHECK(ran)
 	end
 	do CASE "Should allow setting signal after Relation has been used as a component"
 		local A = world:component()
 		local B = world:component()
 		world:add(world:entity(), A)
 		world:added(A, function()
 			ran = true
 		end)
 		world:add(world:entity(), pair(A, B))
 		CHECK(ran)
 	end
 	do CASE "Should invoke signal for the Relation being set as a key despite a pair with Relation having been cached"
 		local A = world:component()
 		local B = world:component()
 		world:add(world:entity(), pair(A, B))
 		world:added(A, function()
 			ran = true
 		end)
 		world:add(world:entity(), A)
 		CHECK(ran)
 	end
 	do CASE "Should not override hook"
 		local A = world:component()
 		local count = 1
 		local function counter()
 			count += 1
 		end
 		world:set(A, jecs.OnAdd, counter)
 		world:added(A, counter)
 		world:set(world:entity(), A, false)
 		CHECK(count == (1 + 2))
 		world:set(world:entity(), A, false)
 		CHECK(count == (1 + (2 * 2)))
 	end
 end)
 TEST("world:range()", function()
-	do CASE "under range start"
+
 	do CASE "spawn entity under min range"
 		local world = jecs.world()
 		world:range(400, 1000)
-		local id = world:entity() :: number
+		CHECK(world.entity_index.alive_count == 399)
-		local e = world:entity(id + 5)
+		local e = world:entity(300)
-		CHECK(e == id + 5)
+		CHECK(world.entity_index.alive_count == 400)
 		local e1 = world:entity(300)
 		CHECK(world.entity_index.alive_count == 400)
 		CHECK(e)
 	end
 	do CASE "axen"
 		local base = jecs.world()
 		base:range(1_000, 2_000)
 		local mirror = jecs.world()
 		mirror:range(3_000, 4_000)
 		mirror:entity() -- NOTE: this fixes the "attempt to index nil with 'dense'" error
 		local foo = base:entity()
 		local bar = mirror:entity(foo)
 		base:delete(base:entity()) -- Removing this line stops the error below from happening
 		local meow = base:entity()
 		mirror:delete(bar)
 		CHECK(jecs.ECS_ID(foo))
 		CHECK(jecs.ECS_ID(meow))
 		local mrrp = mirror:entity(meow) -- jecs, Line 785 - Entity ID is already in use with a different generation
 		CHECK(mrrp == meow)
 	end
 	do CASE "axen2"
 		local world = jecs.world()
 		local mirror = jecs.world()
 		world:range(1000, 2000)
 		mirror:range(3000, 4000)
 		local foo = world:entity() -- 1000
 		local foo_mirror = mirror:entity(foo) -- 1000
 		CHECK(foo == foo_mirror)
 		for index = 1, 5 do
 		  	world:entity()
 		end
 		world:delete(foo)
 		mirror:delete(foo_mirror)
 		local bar = world:entity()
 		local bar_mirror = mirror:entity(bar)
 		CHECK(bar == bar_mirror)
 	end
 	do CASE "delete outside partitioned range"
 		local server = jecs.world()
 		local client = jecs.world()
 		server:range(0, 1000)
 		client:range(1000, 5000)
 		local e1 = server:entity()
 		CHECK((e1::any)< 1000)
 		server:delete(e1)
 		local e2 = client:entity(e1)
 		CHECK(e2 == e1)
 		local A = client:component()
 		client:set(e2, A, true)
 		CHECK(client:get(e2, A))
 		client:delete(e2)
 		local e3 = client:entity()
 		CHECK(ECS_ID(e3) == 1000)
 		local e1v1 = server:entity()
 		local e4 = client:entity(e1v1)
 		CHECK(ECS_ID(e4) == e1::any)
 		CHECK(ECS_GENERATION(e4) == 1)
 		CHECK(not client:contains(e2))
 		CHECK(client:contains(e4))
 	end
 	do CASE "under range start"
 		local world = jecs.world()
 		world:range(400, 1000)
 		local id = world:entity()
 		local e = world:entity(id::any + 5)
 		CHECK(e::any == (id::any) + 5)
 		CHECK(world:contains(e))
 		local e2 = world:entity(399)
 		CHECK(world:contains(e2))
 		world:delete(e2)
 		CHECK(not world:contains(e2))
-		local e2v1 = world:entity(399) :: number
+		local e2v1 = world:entity(399)
 		CHECK(world:contains(e2v1))
 		CHECK(ECS_ID(e2v1) == 399)
 		CHECK(ECS_GENERATION(e2v1) == 0)
@ -790,13 +1248,13 @@ TEST("world:range()", function()
 		CHECK(world:contains(e2))
 		world:delete(e2)
 		CHECK(not world:contains(e2))
-		local e2v1 = world:entity(405) :: number
+		local e2v1 = world:entity(405)
 		CHECK(world:contains(e2v1))
 		CHECK(ECS_ID(e2v1) == 405)
 		CHECK(ECS_GENERATION(e2v1) == 0)
 		world:delete(e2v1)
-		local e2v2 = world:entity(e2v1) :: number
+		local e2v2 = world:entity(e2v1)
 		CHECK(ECS_ID(e2v2) == 405)
 		CHECK(ECS_GENERATION(e2v2) == 0)
 	end
@ -805,9 +1263,10 @@ end)
 TEST("world:entity()", function()
 	do CASE "desired id"
 		local world = jecs.world()
-		local id = world:entity() :: number
+		local id = world:entity()
-		local e = world:entity(id + 5)
+		local offset: jecs.Entity = (id ::any) + 5
-		CHECK(e == id + 5)
+		local e = world:entity(offset)
 		CHECK(e == offset)
 		CHECK(world:contains(e))
 		local e2 = world:entity(399)
 		CHECK(world:contains(e2))
@ -825,7 +1284,7 @@ TEST("world:entity()", function()
 	end
 	do CASE "generations"
 		local world = jecs.world()
-		local e = world:entity() :: any
+		local e = world:entity()
 		CHECK(ECS_ID(e) == 1 + jecs.Rest :: any)
 		CHECK(ECS_GENERATION(e) == 0) -- 0
 		e = ECS_GENERATION_INC(e)
@ -875,11 +1334,11 @@ TEST("world:entity()", function()
 			local e = world:entity()
 			world:delete(e)
 		end
-		local e = world:entity() :: number
+		local e = world:entity()
 		CHECK(ECS_ID(e) == pin)
 		CHECK(ECS_GENERATION(e) == 2^16-1)
 		world:delete(e)
-		e = world:entity() :: number
+		e = world:entity()
 		CHECK(ECS_ID(e) == pin)
 		CHECK(ECS_GENERATION(e) == 0)
 	end
@ -916,6 +1375,7 @@ end)
 TEST("world:query()", function()
 	local N = 2^8
 	do CASE "cached"
 		local world = jecs.world()
 		local Foo = world:component()
@ -952,6 +1412,26 @@ TEST("world:query()", function()
 		world:delete(Foo)
 		CHECK(#q:archetypes() == 0)
 	end
 	do CASE "3 components"
 		local world = jecs.world()
 		local A = world:component() :: jecs.Entity<boolean>
 		local B = world:component() :: jecs.Entity<boolean>
 		local C = world:component() :: jecs.Entity<boolean>
 		local e = world:entity()
 		world:set(e, A, true)
 		world:set(e, B, true)
 		world:set(e, C, true)
 		local q = world:query(A, B, C):cached()
 		local counter = 0
 		for x, a, b, c in q:iter() do
 			counter += 1
 			CHECK(a)
 			CHECK(b)
 			CHECK(c)
 		end
 		CHECK(counter == 1)
 	end
 	do CASE "multiple iter"
 		local world = jecs.world()
 		local A = world:component() :: jecs.Entity<string>
@ -1133,6 +1613,7 @@ TEST("world:query()", function()
 		for i = 1, 9 do
 			local id = world:component()
 			world:component() -- make the components sparsely interleaved
 			components[i] = id
 		end
 		local e1 = world:entity()
@ -1376,7 +1857,7 @@ TEST("world:query()", function()
 		world:add(e2, B)
 		local count = 0
-		for id in world:query(A) :: any do
+		for id in world:query(A) do
 			world:clear(id)
 			count += 1
 		end
@ -1621,7 +2102,9 @@ end)
 TEST("#repro2", function()
 	local world = jecs.world()
 	local Lifetime = world:component() :: Id<number>
 	world:set(Lifetime, jecs.Name, "Lifetime")
 	local Particle = world:entity()
 	world:set(Particle, jecs.Name, "Particle")
 	local Beam = world:entity()
 	local entity = world:entity()
@ -1629,19 +2112,24 @@ TEST("#repro2", function()
 	world:set(entity, pair(Lifetime, Beam), 2)
 	world:set(entity, pair(4 :: any, 5 :: any), 6) -- noise
 	CHECK(world:get(entity, pair(Lifetime, Particle)) == 1)
 	CHECK(world:get(entity, pair(Lifetime, Beam)) == 2)
 	CHECK(world:target(entity, Lifetime, 0) == Particle)
 	CHECK(world:target(entity, Lifetime, 1) == Beam)
 	-- entity_visualizer.components(world, entity)
 	-- print(CHECK(world:has(jecs.ChildOf, jecs.Exclusive)))
 	for e in world:each(pair(Lifetime, __)) do
 		local i = 0
 		local nth = world:target(e, Lifetime, i)
 		while nth do
 			-- entity_visualizer.components(world, e)
 			local data = world:get(e, pair(Lifetime, nth)) :: number
-			data -= 1
+		 	if data > 0 then
-		 	if data <= 0 then
+				data -= 1
                world:remove(e, pair(Lifetime, nth))
            else
                world:set(e, pair(Lifetime, nth), data)
            end
 			i += 1
@ -1649,7 +2137,7 @@ TEST("#repro2", function()
 		end
 	end
-	CHECK(not world:has(entity, pair(Lifetime, Particle)))
+	CHECK(world:get(entity, pair(Lifetime, Particle)) == 0)
 	CHECK(world:get(entity, pair(Lifetime, Beam)) == 1)
 end)
@ -1809,14 +2297,14 @@ TEST("change tracking", function()
 		world:set(e2, Foo, 2)
 		local i = 0
-		for e, new in q1 :: any do
+		for e, new in q1 do
 			i += 1
 			world:set(e, pair(Previous, Foo), new)
 		end
 		CHECK(i == 2)
 		local j = 0
-		for e, new in q1 :: any do
+		for e, new in q1 do
 			j += 1
 			world:set(e, pair(Previous, Foo), new)
 		end
@ -1837,14 +2325,14 @@ TEST("change tracking", function()
 		world:set(testEntity, component, 10)
 		local i = 0
-		for entity, number in q1 :: any do
+		for entity, number in q1 do
 			i += 1
 			world:add(testEntity, tag)
 		end
 		CHECK(i == 1)
-		for e, n in q1 :: any do
+		for e, n in q1 do
 			world:set(e, pair(previous, component), n)
 		end
 	end
--- a/wally.toml
+++ b/wally.toml
@ -1,6 +1,6 @@
 [package]
 name = "ukendio/jecs"
-version = "0.7.2"
+version = "0.9.0-rc.8"
 registry = "https://github.com/UpliftGames/wally-index"
 realm = "shared"
 license = "MIT"
Author	SHA1	Message	Date
Ukendio	0b6bfea5c8	Return nil if nth is over count Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-08-02 23:57:50 +02:00
Ukendio	3cfce10a4a	Increment component records after registering Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-08-02 18:58:19 +02:00
Ukendio	add9ad3939	Support setting signal on cached Relation Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-08-02 06:20:53 +02:00
Ukendio	4153a7cdfe	Monitors and observers need to able to accept pair terms Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-07-29 21:08:23 +02:00
Ukendio	4230a0a797	Version	2025-07-29 21:07:59 +02:00
dai	499afc20cd	Add rbxts typings for signals (#260 ) Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details * Add rbxts typings for signals * Correct arguments	2025-07-27 17:31:31 +02:00
Ukendio	f284de6ec1	Simplying	2025-07-27 17:07:41 +02:00
Ukendio	abc0b1ec22	Fix typos	2025-07-27 17:05:15 +02:00
Marcus	b521fe750a	Bump versions (#259 )	2025-07-27 14:39:43 +02:00
EncodedVenom	998b1d3528	Update query.md - formatting Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-26 18:55:38 -04:00
EncodedVenom	0606bf70f0	Merge pull request #258 from daimond113/fix/remove-entity-type-generic Remove data generic from entity in hooks	2025-07-26 18:48:23 -04:00
daimond113	f2a803c0d8	Remove data generic from entity in hooks	2025-07-27 00:13:14 +02:00
Ukendio	3e46b723e9	Clarify exists usage Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-26 02:50:24 +02:00
Ukendio	3ab1d970e2	Remove dead links	2025-07-26 02:45:13 +02:00
Ukendio	3e2d40e706	Make a table for cleanup	2025-07-26 02:41:40 +02:00
Ukendio	1c2dee57d3	Add some examples	2025-07-26 02:41:18 +02:00
Ukendio	3777585677	Address docs issues	2025-07-26 02:09:28 +02:00
Ukendio	f792c98585	Bump Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-07-24 04:57:06 +02:00
Ukendio	7b43748f18	Fix types issues	2025-07-24 02:25:56 +02:00
Ukendio	666a3ef6de	Fix inner types	2025-07-24 02:04:36 +02:00
Ukendio	69911093a3	No need to check for 0 anymore Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-23 00:38:16 +02:00
Ukendio	59df0bf2a3	Bump Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-07-19 14:30:48 +02:00
Ukendio	3e995c9d7d	Fix iterator not returning correct column for 8+ overloads	2025-07-19 14:29:36 +02:00
Ukendio	78fe5338cf	index component record after archetype gets created Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-18 16:53:32 +02:00
Ukendio	ca0689c92b	Bump	2025-07-18 15:14:39 +02:00
Ukendio	117a5e0ca7	Fix on_remove hook not called on cached edge	2025-07-18 15:13:59 +02:00
Ukendio	d99088ea1e	Bump rc Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-18 00:38:39 +02:00
Ukendio	012b5e2bfa	Make cleanup conditions	2025-07-18 00:37:58 +02:00
Ukendio	54b21001ab	Bump versions	2025-07-17 23:45:56 +02:00
Ukendio	9c09686a69	always check OnDelete condition	2025-07-17 23:45:04 +02:00
Ukendio	ebc39c8b28	Remove debug msgs Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-17 19:38:24 +02:00
Ukendio	7b86084b94	Bump versions	2025-07-17 19:34:29 +02:00
Ukendio	25ceda5cee	Remove alive count upvalue	2025-07-17 18:50:21 +02:00
Ukendio	fc56b6f716	Retrieve updated max_id	2025-07-17 18:47:05 +02:00
dai	c30328527a	Add typings for bulk operations (#257 ) * Add typings for bulk operations * Use Id	2025-07-17 18:25:37 +02:00
Ukendio	c3853023d0	Allow creating an entity with a non-zero generation below range	2025-07-17 18:24:44 +02:00
Ukendio	7b253e1c2a	Remove archetype recycling	2025-07-17 18:07:11 +02:00
Ukendio	210d62d463	Add tests for archetype edges cleanup Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-07-14 15:58:14 +02:00
Ukendio	3f6f8c1739	Export jecs.record for retrieving entity records	2025-07-14 15:57:47 +02:00
Ukendio	7f66d21e6d	Recycle component records	2025-07-14 14:17:18 +02:00
Ukendio	5334d8734d	Export jecs.Component in roblox-ts types	2025-07-14 13:12:41 +02:00
Ukendio	a6ae67250c	Use old interface Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-14 00:47:20 +02:00
Ukendio	9ae32bcce8	Update hook retrieval	2025-07-14 00:45:01 +02:00
Ukendio	f6731069aa	Add backwards relation to edges Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-13 05:15:55 +02:00
Ukendio	c67dfcbd24	Bump versions Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-07-10 12:57:51 +02:00
Ukendio	e1545710db	LF	2025-07-10 12:52:33 +02:00
Ukendio	aa178981dc	Hotfix archetype not being marked dead	2025-07-10 12:51:04 +02:00
Ukendio	ad5ed3b5ea	Increment alive count if under dense Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-07-06 19:42:10 +02:00
Ukendio	362490d25e	Always swap entity	2025-07-06 18:49:28 +02:00
Ukendio	6c1793f853	Remove indirections to entity_index	2025-07-06 17:57:35 +02:00
Ukendio	6b6f6fb961	Bump versions	2025-07-06 17:52:59 +02:00
Ukendio	29350e6ec3	Fix bug to allow deletion outside partitioned range	2025-07-06 17:44:02 +02:00
Ukendio	eed1b6179e	Export ArchetypeOnCreate and ArchetypeOnDelete events	2025-07-06 17:08:29 +02:00
Ukendio	cf94a48a40	Optimized observers	2025-07-06 17:07:43 +02:00
Ukendio	23540e5919	Make iterators simple functions Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-06 09:52:09 +02:00
Ukendio	169ec09ed5	Change monitor to be iterable	2025-07-06 09:48:13 +02:00
Ukendio	a9891abf6d	Make callback optional	2025-07-06 09:42:49 +02:00
Ukendio	6dfb428296	Updated observers	2025-07-06 09:33:31 +02:00
Ukendio	b92cf9ab76	Bump versions	2025-07-06 08:52:17 +02:00
Ukendio	5aedb5e730	Bump wally	2025-07-06 08:51:10 +02:00
Ukendio	1c524f1587	Update TS types	2025-07-06 08:49:10 +02:00
Ukendio	6053038cc1	Move only once during removal of invalidated pair Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-06 08:45:19 +02:00
Ukendio	29305cac5d	Remove second loop in archetype destroy	2025-07-06 07:50:03 +02:00
Ukendio	8fd32978b4	Fix changelog Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-07-04 22:00:23 +02:00
Ukendio	c9d888aeb9	Export try_get_fast Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-04 04:58:20 +02:00
Marcus	155d51a080	Add exclusive relations (#250 ) * Add exclusive relationship * Remove focus * Remove whitespace * Make ChildOf exclusive * Test exclusive relation perf * Inline into world:add * Inline into world:set * Fix benchmark of remove	2025-07-04 04:24:14 +02:00
Marcus	b425150b0c	Add exclusive relations (#250 ) * Add exclusive relationship * Remove focus * Remove whitespace * Make ChildOf exclusive * Test exclusive relation perf * Inline into world:add * Inline into world:set * Fix benchmark of remove	2025-07-04 04:23:28 +02:00
Ukendio	13facc3719	Add inference for IDs in methods Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-03 01:41:06 +02:00
Ukendio	a6ba9f4bd5	Update networking example Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-07-02 20:26:57 +02:00
Ukendio	53f705ac2e	Compare archetype move performance boost Some checks failed analysis / Run Luau Analyze (push) Has been cancelled Details deploy-docs / build (push) Has been cancelled Details publish-npm / publish (push) Has been cancelled Details unit-testing / Run Luau Tests (push) Has been cancelled Details deploy-docs / Deploy (push) Has been cancelled Details	2025-06-30 23:11:05 +02:00
Ukendio	ff4b0bf612	Use btest instead of band	2025-06-30 22:53:40 +02:00
renyang19910211	9b57189c3a	Fix receive_replication.luau removed issue (#243 ) Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-06-30 22:41:29 +02:00
Ukendio	4ff492ceaf	Optimize moving archetype	2025-06-30 22:37:30 +02:00
Ukendio	7c8358656a	unsafe get Some checks are pending analysis / Run Luau Analyze (push) Waiting to run Details deploy-docs / build (push) Waiting to run Details deploy-docs / Deploy (push) Blocked by required conditions Details publish-npm / publish (push) Waiting to run Details unit-testing / Run Luau Tests (push) Waiting to run Details	2025-06-30 01:44:25 +02:00
Marcus	d6e720f200	Optimize removal path (#248 ) * Optimize removal path * Replace eindex_get implementation	2025-06-30 01:06:31 +02:00
Marcus	3c7f3b4eb3	0.7.3 (#247 ) * 0.7.3 * Remove print * fix jecs.meta for adding values	2025-06-30 00:40:03 +02:00