Fix useEffect not running when a dependency changes to nil

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - Fix useContext for uninitialized and/or changing contexts (#26)
 - `useMemo` now computes a new value every render if no array is provided (#29)
+- Fixed `useEffect` not running when a dependency changes to nil (#32)
 
 ## [0.3.0]
 ### Changed

src/init.lua

@@ -81,14 +81,25 @@ function Hooks.new(roact)
 					local lastDependencies = self.effectDependencies[index]
 					if lastDependencies ~= nil then
 						local anythingChanged = false
+						local length = 0
 
 						for dependencyIndex, dependency in pairs(dependsOn) do
+							length += 1
+
 							if lastDependencies[dependencyIndex] ~= dependency then
 								anythingChanged = true
 								break
 							end
 						end
 
+						for _, _ in pairs(lastDependencies) do
+							length -= 1
+						end
+
+						if length ~= 0 then
+							anythingChanged = true
+						end
+
 						if not anythingChanged then
 							continue
 						end