Merge 0546a92 into 574ba20

.github/workflows/ci.yml

@@ -36,6 +36,12 @@ jobs:
         version: "^1.0.1"
         token: ${{ secrets.GITHUB_TOKEN }}
 
+    - name: code quality
+      shell: bash
+      run: |
+        selene src
+        stylua -c src/
+
     - name: install and run darklua
       run: |
         cargo install --git https://gitlab.com/seaofvoices/darklua.git#v0.6.0
@@ -46,12 +52,6 @@ jobs:
         lua -lluacov test/lemur.lua
         luacov -r lcov
 
-    - name: code quality
-      shell: bash
-      run: |
-        selene src
-        stylua -c src/
-
     - name: Report to Coveralls
       uses: coverallsapp/github-action@1.1.3
       with:

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased Changes
 * Add makeThunkMiddleware to inject custom argument ([#69](https://github.com/Roblox/rodux/pull/69)).
+* Add Luau types for actions and reducers ([#70](https://github.com/Roblox/rodux/pull/70)).
 
 ## 3.0.0 (2021-03-25)
 * Revise error reporting logic; restore default semantics from version 1.x ([#61](https://github.com/Roblox/rodux/pull/61)).

foreman.toml

@@ -1,4 +1,4 @@
 [tools]
 rojo = { source = "rojo-rbx/rojo", version = "6.2.0" }
-selene = { source = "Kampfkarren/selene", version = "0.14" }
-stylua = { source = "JohnnyMorganz/StyLua", version = "0.11" }
+selene = { source = "Kampfkarren/selene", version = "0.18.1" }
+stylua = { source = "JohnnyMorganz/StyLua", version = "0.13.1" }

src/combineReducers.lua

@@ -1,7 +1,20 @@
 --[[
 	Create a composite reducer from a map of keys and sub-reducers.
 ]]
-local function combineReducers(map)
+
+local actions = require(script.Parent.types.actions)
+local reducers = require(script.Parent.types.reducers)
+local store = require(script.Parent.types.store)
+
+type AnyAction = actions.AnyAction
+
+export type Reducer<State = any, Action = AnyAction> = reducers.Reducer<State, Action>
+export type ReducersMapObject<State = any, Action = AnyAction> = reducers.ReducersMapObject<State, Action>
+
+type CombinedState<State> = store.CombinedState<State>
+
+local function combineReducers<State>(map: ReducersMapObject): Reducer<CombinedState<State>>
+	-- FIXME LUAU: Remove any cast here once we can constrain the generic type State to a table type
 	return function(state, action)
 		-- If state is nil, substitute it with a blank table.
 		if state == nil then
@@ -16,7 +29,7 @@ local function combineReducers(map)
 		end
 
 		return newState
-	end
+	end :: any
 end
 
 return combineReducers

src/createReducer.lua

@@ -1,5 +1,13 @@
-return function(initialState, handlers)
-	return function(state, action)
+local actions = require(script.Parent.types.actions)
+local reducers = require(script.Parent.types.reducers)
+
+type AnyAction = actions.AnyAction
+
+export type Reducer<State = any, Action = AnyAction> = reducers.Reducer<State, Action>
+
+return function<State>(initialState, handlers): Reducer<State>
+	-- FIXME LUAU: Prefer any cast to avoid assert runtime overhead until typechecker can narrow type of _state_ to be non-nil
+	return function(state: any, action)
 		if state == nil then
 			state = initialState
 		end

src/init.lua

@@ -6,6 +6,15 @@ local loggerMiddleware = require(script.loggerMiddleware)
 local thunkMiddleware = require(script.thunkMiddleware)
 local makeThunkMiddleware = require(script.makeThunkMiddleware)
 
+local actions = require(script.types.actions)
+local reducers = require(script.types.reducers)
+
+export type Action<Type = string> = actions.Action<Type>
+export type AnyAction = actions.AnyAction
+export type ActionCreator<Type, Action, Args...> = actions.ActionCreator<Type, Action, Args...>
+
+export type Reducer<State = any, Action = AnyAction> = reducers.Reducer<State, Action>
+
 return {
 	Store = Store,
 	createReducer = createReducer,

src/makeActionCreator.lua

@@ -1,15 +1,23 @@
---[[
-	A helper function to define a Rodux action creator with an associated name.
+--[[
+	A helper function to define a Rodux action creator with an associated name.
 ]]
-local function makeActionCreator(name, fn)
+
+local actions = require(script.Parent.types.actions)
+
+export type ActionCreator<Type, Action, Args...> = actions.ActionCreator<Type, Action, Args...>
+
+local function makeActionCreator<Type, Action, Args...>(
+	name: Type,
+	fn: (Args...) -> Action
+): ActionCreator<Type, Action, Args...>
 	assert(type(name) == "string", "Bad argument #1: Expected a string name for the action creator")
 
 	assert(type(fn) == "function", "Bad argument #2: Expected a function that creates action objects")
 
 	return setmetatable({
 		name = name,
 	}, {
-		__call = function(self, ...)
+		__call = function(_self: any, ...: Args...): Action & { type: Type }
 			local result = fn(...)
 
 			assert(type(result) == "table", "Invalid action: An action creator must return a table")

src/types/actions.lua

@@ -0,0 +1,14 @@
+export type Action<Type = string> = {
+	type: Type,
+}
+
+export type AnyAction = Action & {
+	[string]: any,
+}
+
+export type ActionCreator<Type, Action, Args...> = typeof(setmetatable(
+	{} :: { name: Type },
+	{} :: { __call: (any, Args...) -> (Action & { type: Type }) }
+))
+
+return nil

src/types/reducers.lua

@@ -0,0 +1,12 @@
+local actions = require(script.Parent.actions)
+
+type AnyAction = actions.AnyAction
+
+export type Reducer<State = any, Action = AnyAction> = (State?, Action) -> State
+
+export type ReducersMapObject<State = any, Action = AnyAction> = {
+	-- TODO Luau: used to be [K in keyof S]: K[S]
+	[string]: Reducer<State, Action>,
+}
+
+return nil

src/types/store.lua

@@ -0,0 +1,5 @@
+type EmptyObject = {}
+
+export type CombinedState<State> = EmptyObject & State
+
+return nil