Scripts are containers that hold Luau code and can modify the properties and behaviors of other objects. You can use scripts to implement the overall logic of your experience to do things like manipulate an object, change its appearance or events, or respond to user interactions.
Scripts can run on the client or server, depending on the functionality you're building. For example, a script that detects and acts on user input must run on the client and a script that validates an in-game consumable must run on the server.
Types of Scripts
Roblox has three types of scripts:
- Script for scripts that can run on the server.
- LocalScript for scripts that can run on a client.
- ModuleScript for reusable modules that can be included in server and client scripts.
To control where scripts run, see the server, client, and replication sections of the data model documentation to understand the appropriate places to place your scripts, so the Roblox engine understands how to run and replicate them.
Creating Scripts
To create script objects in the data model using the Explorer window in Studio:
- Hover over the parent container into which you want to insert a script.
- Click the ⊕ button that appears to the right of the container to open the Insert Object menu.
- Select the type of script you want to insert.
- Rename the script to reflect its purpose using PascalCase.
See our code samples and tutorials for scripting examples.
Module Scripts
ModuleScript objects are reusable scripts that other script objects load by calling the require() function. Module scripts must return exactly one value and run once and only once per Lua environment. As a result, subsequent calls to require() return a cached value.
Multiple scripts can require the same module script, and one module script can be required by both server-side scripts and client-side local scripts.
Structure
Each ModuleScript starts with the following code:
- local module = {} creates an empty table.
- return module returns the table and its members to any script that imports the ModuleScript.
ModuleScript objects return one value that can be any data type except for nil. You can execute arbitrary code in a ModuleScript, but you only need to return what you need in other scripts.
The following example module script returns a getPickupBonus function in the PickupManager table:
Example Module Script
-- ModuleScript in ReplicatedStorage
local PickupManager = {}
local defaultMultiplier = 1.25
local rarityMultipliers = {
common = 10,
uncommon = 20,
rare = 50,
legendary = 100
}
-- Add the getPickupBonus function to the PickupManager module table
function PickupManager.getPickupBonus(rarity)
local bonus = rarityMultipliers[rarity] * defaultMultiplier
return bonus
end
return PickupManager
To call the PickupManager.getPickupBonus function:
Requiring
A ModuleScript runs only when another script imports it using the require() function. If a ModuleScript requires another ModuleScript, a Script or LocalScript must require the first ModuleScript in the chain for any of them to run.
Don't require ModuleScripts in a recursive or circular manner, otherwise Studio throws an error: Requested module was required recursively.
To access a ModuleScript from another script using the require() function:
When you call require() on a ModuleScript, it runs once and returns a single item as a reference. Calling require() again returns the exact same reference, meaning that if you modify a returned table or Instance, subsequent require() calls return that modified reference. The module itself doesn't run multiple times.
If you require() a ModuleScript from both sides of the client-server-boundary, such as in a Script and a LocalScript, then the ModuleScript returns a unique reference for each side.
Patterns
Module scripts have some common patterns that you can use to simplify your code and provide more flexibility over the features Roblox Studio provides. By incorporating these patterns into your development, you can avoid common pitfalls as your Roblox experience grows in size and complexity.
Data Sharing
To associate data with individual objects, you can assign attributes to them or create Configuration folders with value objects such as StringValue or IntValue. However, both approaches are troublesome if you want to add or modify dozens of objects or data values. They also don't store tables or functions.
If you want to modify the same data for multiple copies of the same object or reuse the same data for different objects, store the data in ModuleScripts. It's an easier way for you to reuse the data in other scripts, and you can store tables and functions.
The following example ModuleScript in ReplicatedStorage stores the configuration values for a generic gun:
Weapon Stats
Custom Events
Custom events enable scripts to communicate with each other, but having to keep track of references to individual BindableEvent objects may clutter your code.
You can use ModuleScripts to store BindableEvents and provide custom event handlers that are directly tied to the methods of ModuleScript.
The following ModuleScript in ReplicatedStorage has a custom event that fires when the switch changes state:
Switch Module
-- ModuleScript in ReplicatedStorage named Switch
local Switch = {}
-- Creating bindable so any script can listen to when the switch was changed
local bindableEvent = Instance.new("BindableEvent")
Switch.Changed = bindableEvent.Event
local state = false
function Switch.flip()
state = not state
bindableEvent:Fire(state)
end
return Switch
The following LocalScript in ReplicatedFirst connects a function to call when the Switch.Changed event fires.
-- LocalScript in ReplicatedFirst
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local Switch = require(ReplicatedStorage:WaitForChild("Switch"))
Switch.Changed:Connect(function(newState)
print("Switch state is now", newState)
end
-- Test the flipping a few times
task.wait(1)
Switch.flip()
task.wait(1)
Switch.flip()
Encapsulation
Encapsulation is the practice of creating a layer of abstraction around objects or scripting logic to hide complexity. You can use ModuleScripts to encapsulate Roblox objects with custom Lua functions to simplify code.
For example, you can use encapsulation to:
- Simplify cross-network communication with a single RemoteEvent object.
- Wrap error handling code around sensitive services such as DataStoreService.
- Define custom methods to control or extend Roblox object features.
It's difficult to keep track of dozens of individual RemoteEvent objects to implement networking in your game. You can use a ModuleScript to encapsulate a single RemoteEvent to help simplify this problem. By including a unique id argument, you can still send different network messages while only using a single RemoteEvent.
In the example below, the ModuleScript named NetworkManagerClient encapsulates the RemoteEvent:FireServer() method to include this extra id argument. Additionally, this ModuleScript references the RemoteEvent object itself so you don't have to reference it in other parts of your code. You only need to require this ModuleScript to send network messages and don't need to deal with RemoteEvent objects in the rest of your codebase.
The following ModuleScript in ReplicatedFirst provides an encapsulated function that you can call on your client scripts to send a network message:
Network Module
-- ModuleScript in ReplicatedFirst named NetworkManagerClient
local NetworkManagerClient = {}
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local remoteEvent = ReplicatedStorage:WaitForChild("RemoteEvent")
-- Encapsulating the remote object's FireServer function
function NetworkManagerClient.FireServer(id, ...)
remoteEvent:FireServer(id, ...)
end
return NetworkManagerClient
The following ModuleScript in ServerScriptService uses BindableEvents for every script to connect to a specific id. When a client sends a network message, each BindableEvent associated with the specified id fires.
-- ModuleScript in ServerScriptService named NetworkManagerServer
local NetworkManagerServer = {}
local networkSignalList = {}
function NetworkManagerServer.GetServerEventSignal(id)
local bindableEvent = Instance.new("BindableEvent")
-- Linking the new BindableEvent to the id
table.insert(networkSignalList, {
id = id;
bindableEvent = bindableEvent;
})
return bindableEvent.Event
end
-- Connecting to
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local remoteEvent = ReplicatedStorage:WaitForChild("RemoteEvent")
remoteEvent.OnServerEvent:Connect(function(player, id, ...)
-- Finding every bindable event that matches the id of the received remote event
for _, signal in next, networkSignalList do
if signal.id == id then
signal.bindableEvent:Fire(player, ...)
end
end
end)
return NetworkManagerServer
The following LocalScript sends a message with the id "RequestA" with an optional "Hello" argument.
The following Script connects to the network message id "RequestA" and prints out a statement with any additional parameters when it receives the request.
-- Script in ServerScriptService
local ServerScriptService = game:GetService("ServerScriptService")
local NetworkManagerServer = require(ServerScriptService:WaitForChild("NetworkManagerServer"))
NetworkManagerServer.GetServerEventSignal("RequestA"):Connect(function(player, ...)
print("Received RequestA from", player, ...)
end)