I have been folowing the Roblox developpers data storing tutorial "Saving Player Data" from where I got the module script code.

http://developer.roblox.com/en-us/articles/Saving-Player-Data


-- Set up table to return to any script that requires this module script
local PlayerStatManager = {}
local DataStoreService = game:GetService("DataStoreService")
local playerData = DataStoreService:GetDataStore("PlayerData")

-- Table to hold player information for the current session
local sessionData = {}



local AUTOSAVE_INTERVAL = 60

     
-- Function that other scripts can call to change a player's stats
function PlayerStatManager:ChangeStat(player, statName, value)
	local playerUserId = "Player_" .. player.UserId
    assert(typeof(sessionData[playerUserId][statName]) == typeof(value), "ChangeStat error: types do not match")
    if typeof(sessionData[playerUserId][statName]) == "number" then
    	sessionData[playerUserId][statName] = sessionData[playerUserId][statName] + value
		print(sessionData[playerUserId][statName])
    else
    	sessionData[playerUserId][statName] = value
    end
end
     
-- Function to add player to the "sessionData" table
local function setupPlayerData(player)
	local playerUserId = "Player_" .. player.UserId
	local success, data = pcall(function()
		return playerData:GetAsync(playerUserId)
	end)
	if success then
		
		
		if data then
			print("Data exists for this player")
			sessionData[playerUserId] = data
			
		else
			print("Data store is working, but no current data for this player")
			sessionData[playerUserId] = {Money=18, Exp=17}
			
		end
	else
		warn("Cannot access data store for player!")
	end
end
 
-- Function to save player's data
local function savePlayerData(playerUserId)
	if sessionData[playerUserId] then
		local tries = 0
		local success
		repeat
			tries = tries + 1
			success = pcall(function()
				playerData:SetAsync(playerUserId, sessionData[playerUserId])
			end)
			if not success then wait(1) end
		until
		tries == 3 or success
		if not success then
			warn("Cannot save data for player!")
		end
	end
end
     
    -- Function to save player data on exit
    local function saveOnExit(player)
    	local playerUserId = "Player_" .. player.UserId
    	savePlayerData(playerUserId)
    end

-- Function to periodically save player data
local function autoSave()
	while wait(AUTOSAVE_INTERVAL) do
		for playerUserId, data in pairs(sessionData) do
			savePlayerData(playerUserId)
		end --sauvegarde les donnés
	end
end
 
-- Start running "autoSave()" function in the background
spawn(autoSave)
     
-- Connect "setupPlayerData()" function to "PlayerAdded" event
game.Players.PlayerAdded:Connect(setupPlayerData)
     
-- Connect "saveOnExit()" function to "PlayerRemoving" event
game.Players.PlayerRemoving:Connect(saveOnExit)

-- Return the PlayerStatManager table to external scripts can access it.
return PlayerStatManager

What I am trying to do is to use this function in another script to change Money's variable value : function PlayerStatManager:ChangeStat(player, statName, value) To do so I added return PlayerStatManager to the module script.

Here is the test script i did to use that function:

local PlayerStatManager = require(game.ServerScriptService.DataModule)
local Money = require(game.ServerScriptService.DataModule)



local value = 10 -- can't insert a number as an argument, "expected identifier when parsing varible name, got '10'" error
local i = 0

repeat
	wait(1)
	i = i + 1
	function PlayerStatManager:ChangeStat(player, Money, value)
	
	end
	print(i)
	
until
	i==4

Here is the error i get :

"ServerScriptService.DataModule:17: attempt to index nil with 'UserId' "

This mean for me that player, as an argument is nil, wich I don't understand because it's used like that in the module script.

I also can't isert directly a number as an argument of the function, i have the folowing error:

" expected identifier when parsing varible name, got '10' "

To sum up :

  • Why 'player' is nil as an argument despite it is used like that in the module script?

  • Why I can't use a number as an argument?

  • What is the correct code to use the function in another script?

Here is the full output if it can be useful :

17:15:09.409 - ServerScriptService.DataModule:17: attempt to index nil with 'UserId' 17:15:09.409 - Stack Begin 17:15:09.409 - Script 'ServerScriptService.DataModule', Line 17 - function ChangeStat 17:15:09.410 - Script 'ServerScriptService.Leaderboards', Line 10 17:15:09.410 - Stack End Data exists for this player 17:15:10.766 - ERROR running in studio Data loaded 1 2 3 4 17:15:11.546 - MouseButton1Click is not a valid member of ImageLabel 17:15:11.547 - Stack Begin 17:15:11.547 - Script 'Players.Aut0_doubleAK47.PlayerGui.Backpack Gui.Frame.inventaire', Line 4 17:15:11.547 - Stack End 17:15:21.998 - Disconnect from 127.0.0.1|58624

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