NamedSignal

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Quick Start ​

This guide shows the basics of using NamedSignal — creating, connecting, and firing signals.

Require and Create ​

Requiring the module returns a table with a new constructor:

luau
local Signal = require(path.to.module)

local helloEvent = Signal.new()

Type Annotation ​

To utilize NamedSignal's main quality-of-life feature, named parameters, you should annotate the type of the Signal.

You can do this in several ways:

luau
local helloEvent: Signal.Signal<(subject: string) -> ()> = Signal.new() :: any
luau
local helloEvent = Signal.new() :: Signal.Signal<(subject: string) -> ()>
luau
local helloEvent = Signal.new<<(subject: string) -> ()>>()

All three approaches achieve the same result, use whichever fits your requirements.

[*] Colloquial name for explicit type parameter instantiation, borrowed from Rust (::<T>).

Connect a Listener ​

Once typed, Luau can automatically fill in the connecting function for you:

luau
local helloConnection = helloEvent:Connect(function(subject: string)
	print(`Hello, {subject}!`)
end)

TIP: Connection Lifecycle

Signal:Connect() returns a Connection object, which can later be used to disconnect the listener by calling Connection:Disconnect().

Fire the Signal ​

Trigger the event by calling Signal:Fire() with the expected arguments:

luau
helloEvent:Fire("world")

Full Example ​

All together:

luau
local Signal = require(path.to.module)

local helloEvent = Signal.new<<(subject: string) -> ()>>()

local helloConnection = helloEvent:Connect(function(subject: string)
	print(`Hello, {subject}!`)
end)

helloEvent:Fire("world")

And voilà! You should get the following output when running the script:

txt
Hello, world!

Going Cross-Script ​

The most common way of sharing signals across scripts is to place it inside a table, whether at the module-level, as a member in a class, or elsewhere:

luau
local Module = {}

Module.fooEvent = Signal.new<<(cat: "meow") -> ()>>() 

return Module

Other scripts can then access the created event by requiring the module that contains it:

luau
local Module = require(path.to.module)

Module.fooEvent:Connect(function(cat: "meow")
	print(cat)
end)