Unable to cast array and index nil with waitforchild

Help and Feedback Scripting Support
#1

Hello,
I am working on a data saving script and for some reason I am getting two errors. The first one being

ServerScriptService.Script:17: attempt to index nil with 'WaitForChild'

And the second one being:

 Unable to cast to Array

Here is the script:

  local DataStore =  game:GetService("DataStoreService"):GetDataStore("ammo")
local toolname = "10mm"
local valuename = "ammo"
local value2name = "maxammo"
game.Players.PlayerAdded:Connect(function(player)
	local function onCharacterAdded(character)
		local backpack = player:WaitForChild("Backpack")
		local tool = backpack:FindFirstChild(toolname)
		local value = tool:WaitForChild(valuename)
		local value2 = tool:WaitForChild(value2name)

		
	end
	player.CharacterAdded:Connect(onCharacterAdded)
	local backpack = player:WaitForChild("Backpack")
	local tool = backpack:FindFirstChild(toolname)
	local value = tool:WaitForChild(valuename)
	local value2 = tool:WaitForChild(value2name)
	local data
	local key = "Player_".. player.UserId
	local success, errormessage = pcall(function()
		data = DataStore:GetAsync(key)
	end)
	if success then
		value.Value = data
		value2.Value = data
	elseif data == nil then
		value.Value = 0
		value2.Value = 0
	else
		warn(errormessage)
	end
end)

game.Players.PlayerRemoving:Connect(function(player)
	local key = "Player_".. player.UserId

	local data1 = player.Backpack:WaitForChild("10mm"):WaitForChild("ammo").Value
	local data2 = player.Backpack:WaitForChild("10mm"):WaitForChild("maxammo").Value
    
	DataStore:SetAsync(key, data1, data2)
end)
#2

Tried findfirstchild, waitforchild, etc and it keeps saying it doesn’t work and unable to cast array.

#3

just do

if tool then
  local value = tool:WaitForChild(valuename)
  local value2 = tool:WaitForChild(value2name)
end

Since if the tool doesn’t exist it will throw that error.

Also for the second error. DataStores:SetAsync() only takes data as the second arguement not the 3rd.

Just save the data in an array.

DataStore:SetAsync(key, {data1, data2})
#4

I did the if tool then, but the problem now is that the data doesn’t have the values. It is red underlined.

#5

image
image1920×1080 237 KB

Screenshot of the script.

#7

Also, the tool is in the starterpack by default. Still unsure how to get the two values.

#8

Give this a go

local DataStore =  game:GetService("DataStoreService"):GetDataStore("ammo")
local toolname = "10mm"
local valuename = "ammo"
local value2name = "maxammo"
game.Players.PlayerAdded:Connect(function(player)
	local backpack = player:WaitForChild("Backpack")
	local tool = backpack:WaitForChild(toolname)
	local value = tool:WaitForChild(valuename)
	local value2 = tool:WaitForChild(value2name)
	local data
	local key = "Player_".. player.UserId
	local success, errormessage = pcall(function()
		data = DataStore:GetAsync(key)
	end)
	if not success then
		warn(key,errormessage)
		return
	end
	if data then
		value.Value = data[1]
		value2.Value = data[2]
	else
		value.Value = 0
		value2.Value = 0
	end
end)

game.Players.PlayerRemoving:Connect(function(player)
	local key = "Player_".. player.UserId

	local data1 = player.Backpack:WaitForChild("10mm"):WaitForChild("ammo").Value
	local data2 = player.Backpack:WaitForChild("10mm"):WaitForChild("maxammo").Value

	DataStore:SetAsync(key, {data1,data2})
end)
#9

Infinite yield possible on line 7.

#10

try

	local tool = backpack:WaitForChild(toolname,30)
#11

Saves the data now, but doesn’t load it at all.

#12

try loading it one more time so it properly move the data to table format

#13

Alright, I did that and then I realized something. After looking at my old script and having a friend play test the game, it appears the ammo data saves and loads for everyone else with my old script. Doesn’t save/load for me but does for them, so weird. But thanks for your help.