Signal

Summary

Methods

• Connect(): Connection
• Fire(): nil
• Once(): Connection
• Wait(): any

Overview

Signal is a data type that is used in user-defined functions, otherwise known as listeners, to trigger when something happens in the game.
The Signal might also happen to pass arguments to each listener depending on which event it is.

Methods

Connect()

Connects the given function and creates a new Connection.

local part = workspace:FindFirstChild("Baseplate")
if not part then
    return
end

local connection = part.Changed:Connect(function(message)
    print(message)
end)

part.Changed:Fire("changed")

Fire()

Synchronously invokes connected callbacks with the supplied arguments.

local part = workspace:FindFirstChild("Baseplate")
if not part then
    return
end

local signal = part.Changed
signal:Connect(function(message)
    print(message)
end)
signal:Fire("Hello")

Once()

Connects the given function and creates a new Connection.
Once will run the function only once, unlike the other methods.

local part = workspace:FindFirstChild("Baseplate")
if not part then
    return
end

part.Changed:Once(function(message)
    print(message)
end)

part.Changed:Fire("first")
part.Changed:Fire("second") -- the callback does not run again

Wait()

Yields the current thread until the Signal fires. Wait() returns arguments passed by the signal.

new()

Signal.new was available in the earlier 0.3.4 tests, but the global Signal was nil in a Vortex Studio 0.3.8 server Script. Use an engine-owned signal, such as Part.Changed, in the current release.

Vortex Studio 0.3.4 notes

Connect, Once, Wait, and Fire were revalidated on Part.Changed in both Script and LocalScript; a manually fired signal delivered once before disconnect and not afterward. ConnectParallel remains absent.

In a LocalScript, UserInputService.InputBegan:Once and :Wait both delivered the same right-mouse-button input. A normal Script still has no UserInputService.

The Part attribute/property-change signals used in the examples are connectable, but mutating the corresponding attribute or property still did not deliver callbacks in 0.3.4.

In 0.3.4, lowercase connect and fire work on Part.Changed, and Signal.new creates a standalone signal whose Connect callback receives a manually fired argument. This was confirmed in both Script and LocalScript.

In Vortex Studio 0.3.8, an engine-owned Part.Changed signal still exposed Connect, Fire, Once, and Wait. A manual Fire("yes") reached a connected callback once; after Disconnect(), a second fire did not reach it. The global Signal constructor was nil in the tested server Script.