Monitors and observers need to able to accept pair terms

addons/ob.luau

@@ -69,6 +69,9 @@ local function observers_new<T...>(
 	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
@@ -151,7 +154,7 @@ local function monitors_new<T...>(
 			i += 1
 			entities[i] = entity
 			if callback ~= nil then
-				callback(entity, id, value)
+				callback(entity, jecs.OnAdd)
 			end
 		end
 	end
@@ -164,6 +167,9 @@ local function monitors_new<T...>(
 	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

demo/src/ReplicatedStorage/main.client.luau

@@ -1,12 +1,11 @@
 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)

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 = {

test/addons/observers.luau

@@ -2,11 +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 FOCUS = test.FOCUS
 local ob = require("@addons/ob")
 
 TEST("addons/observers", function()
-	local world = jecs.world()
 
+	local world = jecs.world()
+	do CASE "monitors should accept pairs"
+		local A = world:component()
+		local B = world:component()
+
+		local c = 1
+		ob.monitor(world:query(jecs.pair(A, B)), function (_, event)
+			c += 1
+		end)
+
+		local child = world:entity()
+		world:add(child, jecs.pair(A, B))
+		CHECK(c == 2)
+
+		world:remove(child, jecs.pair(A, B))
+		CHECK(c == 3)
+	end
 	do CASE "Ensure ordering between signals and observers"
 		local A = world:component()
 		local B = world:component()