Lua attempt to concatenate a nil value

[Lava Titan]

hey, I created this function to use on donation items for example, and create few lines in a log file with details of usage

and seems I'm missing something cuz getting an error that I'm not able to understand

compat.lua

function logItemUsage(playerId, itemId, directory)
    local log_str=""
    local player = Player(playerId)
    local item = ItemType(itemId)

    log_str = "Player Name: "..player:getName().."\nItem ID: "..item:getId().."\nItem Name: "..item:getName()..""

    if log_str ~= "" then
        local file = io.open(directory, "a+")
        file:write("------------------------------------------------------------\nDay: " .. os.date("%d/%m/%Y") .. "\nTime: " .. os.date("%H:%M:%S") .. "\n"..log_str.."\n------------------------------------------------------------\n")
        file:close()
    end
return true
end

actionscript.lua

logItemUsage(player:getId(), item:getId(), 'data/items.log')

error in console:

Thanks in advance

 

[The Matrix]

How about this

function logItemUsage(playerId, itemId, directory)
    local player = Player(playerId)
    local item = ItemType(itemId)

    if not player or not item then
        return false
    end
   
    local log_str = "Player Name: "..player:getName().."\nItem ID: "..item:getId().."\nItem Name: "..item:getName()
    local file = io.open(directory, "a+")
    file:write("------------------------------------------------------------\nDay: " .. os.date("%d/%m/%Y") .. "\nTime: " .. os.date("%H:%M:%S") .. "\n"..log_str.."\n------------------------------------------------------------\n")
    file:close()
    return true
end

 

[Lava Titan]

wow can't belive I missed that XD

thanks it works