Checking if variable has changed

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#1

I am creating a module that handles settings for games. I am adding signals to it using the Signals module that fire whenever a setting is changed.

However, it’s not working. Not the signal, but detecting if the setting has changed.

local function heartbeat()
	for name, setting in pairs(settingsModule.Settings) do
		local oldSetting = oldSettings[name]
		
		if oldSetting then
			if oldSetting.Value ~= setting.Value then
				settingsModule.SettingChanged:Fire(setting)
				setting.Changed:Fire(setting.Value)
			end
		else
			settingsModule.SettingAdded:Fire(setting)
		end
	end
	
	oldSettings = settingsModule.Settings
end

runService.Heartbeat:Connect(heartbeat)

This is what I have for it right now. Unfortunately, the signal doesn’t fire, and if I add a print, it won’t do that either.

I thought it might be oldSettings = settingsModule.Settings, so I made it individually set each setting, but that didn’t work either.

I’m thinking the oldSettings variable could just be referencing the settingsModule.Settings table so it’s always the same, but I don’t know how I can get around that.

Any thoughts?

(Don’t be fooled by the Value “property”! The settings are not objects, they are tables!)

#2

is setting a value in workspace? if so then you could use setting.Changed and connect a function to fire everytime that happens

1 Like
#3

They are not objects. I would rather not resort to using objects to accomplish this. I’m sure what I’m trying to do is possible but I’m not sure how.

2 Likes
#4

First of all the Signal module you use is unlisted and none of the devs ik seems to use it (not saying that you shouldn’t but these are top devs), a better pick would be stravants GoodSignal which afaik is the industry standard as it has already been benchmarked and is already proved to be superior to the competition.

1 Like
#5

The problem is not the Signal module. I’m attempting to detect when a variable within a table, or a “setting”, has changed.

1 Like
#6

Yep, here’s the stats to back it up: Lua Signal Class Comparison & Optimal `GoodSignal` Class
GoodSignal is the industry standard as you say.
Your code looks good and should work as intended from what I can see.
Try disconnecting it from the RS loop, and instead run it every X seconds. Print out the oldSettings and the currentSettings → are they what you expect?

1 Like
#7

Value is always the same when I print them both out. I think this is because I’m changing oldSettings to reference settingsModule.Settings- and not actually changing oldSettings to the value of settingsModule.Settings. How can I work around this?

New code if it's useful 
local function changedLoop()
	while task.wait(0.1) do
		print(oldSettings)
		print(settingsModule.Settings)
		
		for name, setting in pairs(settingsModule.Settings) do
			local oldSetting = oldSettings[name]

			if oldSetting then
				if oldSetting.Value ~= setting.Value then
					settingsModule.SettingChanged:Fire(setting)
					setting.Changed:Fire(setting.Value)
				end
			else
				settingsModule.SettingAdded:Fire(setting)
			end
		end

		oldSettings = settingsModule.Settings
	end
end

task.spawn(changedLoop)
#9

I’m not sure how your module looks, but for barebone explaining and suggesting it should do:

local module = {}
module.Settings = {
	VFX = false
}

function module:getSettingsMetatable()
	return setmetatable({}, {__newindex = function(t, index, value)
		print(self.Settings)
		self.Settings[index] = value
		print(self.Settings)
	end})
end

return module
------Running
local Settings = require(game.ReplicatedStorage.ModuleScript)
local SettingsMeta = Settings:getSettingsMetatable()
SettingsMeta["VFX"] = true
----- Output
{
   ["VFX"] = false
}  -  Client - ModuleScript:7

{
   ["VFX"] = true
}  -  Client - ModuleScript:9

__newindex metamethod looks like the best option to me. Hope this will help you out!

#10

I have solved this problem using a more advanced table.clone() function. Turns out I was referencing the new Settings table.

#11

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