add gs

RCCService2018/content/LuaPackages/RoactRoduxImpl/connect.lua

@@ -0,0 +1,113 @@
+local Roact = require(script.Parent.Parent.Roact)
+
+local storeKey = require(script.Parent.storeKey)
+
+local function shallowEqual(a, b)
+	for key, value in pairs(a) do
+		if b[key] ~= value then
+			return false
+		end
+	end
+
+	for key, value in pairs(b) do
+		if a[key] ~= value then
+			return false
+		end
+	end
+
+	return true
+end
+
+--[[
+	Joins two tables together into a new table
+]]
+local function join(a, b)
+	local result = {}
+
+	for key, value in pairs(a) do
+		result[key] = value
+	end
+
+	for key, value in pairs(b) do
+		result[key] = value
+	end
+
+	return result
+end
+
+-- A version of 'error' that outputs over multiple lines
+local function errorLines(...)
+	error(table.concat({...}, "\n"))
+end
+
+local function connect(mapStoreToProps)
+	local rootTrace = debug.traceback()
+
+	local mapConnect = function(store, props)
+		local result = mapStoreToProps(store, props)
+
+		if type(result) ~= "table" then
+			errorLines(
+				"mapStoreToProps must return a table! Check the function passed into 'connect' at:",
+				rootTrace
+			)
+		end
+
+		return result
+	end
+
+	return function(component)
+		if component == nil then
+			error("Expected component to be passed to connection, got nil.")
+		end
+
+		local name = ("Connection(%s)"):format(
+			tostring(component)
+		)
+		local Connection = Roact.Component:extend(name)
+
+		function Connection:init(props)
+			local store = self._context[storeKey]
+
+			if not store then
+				errorLines(
+					"Cannot initialize Roact-Rodux component without being a descendent of StoreProvider!",
+					("Tried to wrap component %q"):format(tostring(component)),
+					"Make sure there is a StoreProvider above this component in the tree."
+				)
+			end
+
+			self.store = store
+
+			self.state = {
+				storeProps = mapConnect(store, props),
+			}
+		end
+
+		function Connection:didMount()
+			self.eventHandle = self.store.changed:connect(function(state)
+				local storeProps = mapConnect(self.store, self.props)
+
+				if not shallowEqual(self.state.storeProps, storeProps) then
+					self:setState({
+						storeProps = storeProps
+					})
+				end
+			end)
+		end
+
+		function Connection:willUnmount()
+			self.eventHandle:disconnect()
+		end
+
+		function Connection:render()
+			local props = join(self.props, self.state.storeProps)
+
+			return Roact.createElement(component, props)
+		end
+
+		return Connection
+	end
+end
+
+return connect