Merge af37c57 into 38ef143

lib/Store.lua

@@ -23,8 +23,9 @@ Store.__index = Store
 	Reducers do not mutate the state object, so the original state is still
 	valid.
 ]]
-function Store.new(reducer, initialState)
+function Store.new(reducer, initialState, middlewares)
 	assert(typeof(reducer) == "function", "Bad argument #1 to Store.new, expected function.")
+	assert(middlewares == nil or typeof(middlewares) == "table", "Bad argument #3 to Store.new, expected nil or table.")
 
 	local self = {}
 
@@ -46,6 +47,15 @@ function Store.new(reducer, initialState)
 	end)
 	table.insert(self._connections, connection)
 
+	if middlewares then
+		local dispatch = Store.dispatch
+		for _, middleware in ipairs(middlewares) do
+			dispatch = middleware(dispatch)
+		end
+
+		self.dispatch = dispatch
+	end
+
 	return self
 end
 

lib/Store.spec.lua

@@ -24,6 +24,42 @@ return function()
 			store:destruct()
 		end)
 
+		it("should instantiate with a reducer, initial state, and middlewares", function()
+			local store = Store.new(function(state, action)
+				return state
+			end, "initial state", {})
+
+			expect(store).to.be.ok()
+			expect(store:getState()).to.equal("initial state")
+
+			store:destruct()
+		end)
+
+		it("should modify the dispatch method when middlewares are passed", function()
+			local middlewareInvokeCount = 0
+
+			local function reducer(state, action)
+				return state
+			end
+
+			local function testMiddleware(next)
+				return function(store, action)
+					middlewareInvokeCount = middlewareInvokeCount + 1
+					next(store, action)
+				end
+			end
+
+			local store = Store.new(reducer, "initial state", { testMiddleware })
+
+			store:dispatch({
+				type = "test"
+			})
+
+            expect(middlewareInvokeCount).to.equal(1)
+
+			store:destruct()
+        end)
+
 		it("should send an initial action with a 'type' field", function()
 			local lastAction
 			local callCount = 0

lib/init.lua

@@ -1,9 +1,11 @@
 local Store = require(script.Store)
 local createReducer = require(script.createReducer)
 local combineReducers = require(script.combineReducers)
+local loggerMiddleware = require(script.loggerMiddleware)
 
 return {
 	Store = Store,
 	createReducer = createReducer,
 	combineReducers = combineReducers,
+	loggerMiddleware = loggerMiddleware,
 }

lib/loggerMiddleware.lua

@@ -0,0 +1,41 @@
+local indentStr = "    "
+
+local function prettyPrint(t, indent)
+	indent = indent or 1
+	local outputBuffer = {
+		"{\n"
+	}
+
+	for key, value in pairs(t) do
+		local strKey = tostring(key)
+
+		table.insert(outputBuffer, indentStr:rep(indent + 1))
+		table.insert(outputBuffer, strKey)
+		table.insert(outputBuffer, " = ")
+
+		if type(value) == "table" then
+			table.insert(outputBuffer, prettyPrint(value, indent + 1))
+			table.insert(outputBuffer, "\n")
+		else
+			table.insert(outputBuffer, tostring(value))
+			table.insert(outputBuffer, "; (")
+			table.insert(outputBuffer, typeof(value))
+			table.insert(outputBuffer, ")\n")
+		end
+	end
+
+	table.insert(outputBuffer, indentStr:rep(indent))
+	table.insert(outputBuffer, "}")
+
+	return table.concat(outputBuffer, "")
+end
+
+local function loggerPlugin(next)
+	return function(store, action)
+		print("Action dispatched:", prettyPrint(action))
+		next(store, action)
+		print("State changed to:", prettyPrint(store:getState()))
+	end
+end
+
+return loggerPlugin