ModuleScript

Inherits from: LuaSourceContainer → Instance → Object

A ModuleScript is a script type that returns exactly one value by a call to LuaGlobals.require(). ModuleScripts run once and only once per Luau environment and return the exact same value for subsequent calls to LuaGlobals.require().

ModuleScripts are essential objects for adhering to the "Don't Repeat Yourself" (DRY) principle, allowing you to write a function only once and use it everywhere. Having multiple copies of a function is problematic when you need to change their behavior, so you should define functions or groups of functions in ModuleScripts and have your Scripts and LocalScripts call LuaGlobals.require() on those modules.

It's important to know that return values from ModuleScripts are independent with regards to Scripts and LocalScripts, and other environments like the Command Bar. Using LuaGlobals.require() on a ModuleScript in a LocalScript will run the code on the client, even if a Script did so already on the server. Therefore, be careful if you're using a ModuleScript on the client and server at the same time, or debugging it within Studio.

Note that the first call to LuaGlobals.require() will not yield (halt) unless the ModuleScript yields (calls task.wait() for example), in which case the current thread that called LuaGlobals.require() will yield until the ModuleScript returns a value. If a ModuleScript is attempting to LuaGlobals.require() another ModuleScript that in turn tries to LuaGlobals.require() it, the thread will hang and never halt (cyclic LuaGlobals.require() calls do not generate errors). Be mindful of your module dependencies in large projects!

If a ModuleScript is uploaded to Roblox and the root module has the name set to MainModule, it can be uploaded as a model and required using LuaGlobals.require() with the model's asset ID. Then it can be loaded into your experience, although this logic only works on the server and will error on the client. If other users want to use the module, it must be public.

Inherits from: LuaSourceContainer

Memory category: Script

Code samples: View on Creator Hub (Simple-ModuleScript-Example, Simple-ModuleScript-Usage).

Properties

Name	Type / Returns	Description
ModuleScript.LinkedSource	ContentId	Used to store a URL that points to an online script source. Binds the online code to the script's `Script.Source`.
ModuleScript.Source	ProtectedString	The code to be executed.

Inherited from Instance

Name	Type / Returns	Description
Instance.Archivable	boolean	Determines if an `Instance` and its descendants can be cloned using `Instance:Clone()`, and can be saved/published.
Instance.archivable	boolean
Instance.Capabilities	SecurityCapabilities	The set of capabilities allowed to be used for scripts inside this container.
Instance.IsInSandbox	boolean	Indicates whether the instance is inside a sandboxed container.
Instance.Name	string	A non-unique identifier of the `Instance`.
Instance.Parent	Instance	Determines the hierarchical parent of the `Instance`.
Instance.PredictionMode	PredictionMode	Reflects the client-side prediction mode applied to the instance under server-authoritative physics.
Instance.RobloxLocked	boolean	A deprecated property that used to protect `CoreGui` objects.
Instance.Sandboxed	boolean	When enabled, the instance can only access abilities in its `Capabilities` list.
Instance.UniqueId	UniqueId	A unique identifier for the instance.

Inherited from Object

Name	Type / Returns	Description
Object.ClassName	string	A read-only string representing the class this `Object` belongs to.
Object.className	string

ModuleScript.LinkedSource

Deprecated. This property is now replaced by packages which has greater functionality.

Used to store a URL that points to an online script source. Binds the online code to the script's Script.Source.

Field	Value
type	ContentId
tags	["Deprecated"]
security	{"read":"None","write":"None"}
thread safety	ReadSafe
category	Data
serialization	{"can_load":true,"can_save":true}
capabilities	["LoadUnownedAsset"]

ModuleScript.Source

The code to be executed.

If you want to read or modify a script that the user has open, consider using the ScriptEditorService to interact with the Script Editor instead.

Field	Value
type	ProtectedString
security	{"read":"None","write":"None"}
thread safety	ReadSafe
category	Data
serialization	{"can_load":true,"can_save":true}
capabilities	["PluginOrOpenCloud"]

Methods

Inherited from Instance

Name	Type / Returns	Description
Instance:AddTag	()	Applies a tag to the instance.
Instance:children	Instances	Returns an array of the object's children.
Instance:ClearAllChildren	()	This method destroys all of an instance's children.
Instance:Clone	Instance	Create a copy of an instance and all its descendants, ignoring instances that are not `Archivable`.
Instance:clone	Instance
Instance:Destroy	()	Sets the `Instance.Parent` property to `nil`, locks the `Instance.Parent` property, disconnects all connections, and calls `Destroy()` on all children.
Instance:destroy	()
Instance:FindFirstAncestor	Instance?	Returns the first ancestor of the `Instance` whose `Instance.Name` is equal to the given name.
Instance:FindFirstAncestorOfClass	Instance?	Returns the first ancestor of the `Instance` whose `Object.ClassName` is equal to the given className.
Instance:FindFirstAncestorWhichIsA	Instance?	Returns the first ancestor of the `Instance` for whom `Object:IsA()` returns true for the given className.
Instance:FindFirstChild	Instance?	Returns the first child of the `Instance` found with the given name.
Instance:findFirstChild	Instance
Instance:FindFirstChildOfClass	Instance?	Returns the first child of the `Instance` whose `ClassName` is equal to the given class name.
Instance:FindFirstChildWhichIsA	Instance?	Returns the first child of the `Instance` for whom `Object:IsA()` returns true for the given className.
Instance:FindFirstDescendant	Instance?	Returns the first descendant found with the given `Instance.Name`.
Instance:GetActor	Actor?	Returns the `Actor` associated with the Instance, if any.
Instance:GetAttribute	Variant	Returns the value which has been assigned to the given attribute name.
Instance:GetAttributeChangedSignal	RBXScriptSignal	Returns an event that fires when the given attribute changes.
Instance:GetAttributes	Dictionary	Returns a dictionary of the instance's attributes.
Instance:GetChildren	Instances	Returns an array containing all of the instance's children.
Instance:getChildren	Instances
Instance:GetDebugId	string	Returns a coded string of the debug ID used internally by Roblox.
Instance:GetDescendants	Instances	Returns an array containing all of the descendants of the instance.
Instance:GetFullName	string	Returns a string describing the instance's ancestry.
Instance:GetStyled	Variant	Returns the styled or explicitly modified value of the specified property, or else the default property value if it hasn't been styled/modified.
Instance:GetStyledPropertyChangedSignal	RBXScriptSignal	Returns an event that fires when the given style property changes on the instance.
Instance:GetTags	Array	Gets an array of all tags applied to the instance.
Instance:HasTag	boolean	Check whether the instance has a given tag.
Instance:IsAncestorOf	boolean	Returns true if an `Instance` is an ancestor of the given descendant.
Instance:IsDescendantOf	boolean	Returns `true` if an `Instance` is a descendant of the given ancestor.
Instance:isDescendantOf	boolean
Instance:IsPropertyModified	boolean	Returns `true` if the value stored in the specified property is not equal to the code-instantiated default.
Instance:QueryDescendants	Instances	Returns an array containing all descendants of the instance that match the `selector` string.
Instance:Remove	()	Sets the object's `Parent` to `nil`, and does the same for all its descendants.
Instance:remove	()
Instance:RemoveTag	()	Removes a tag from the instance.
Instance:ResetPropertyToDefault	()	Resets a property to its default value.
Instance:SetAttribute	()	Sets the attribute with the given name to the given value.
Instance:WaitForChild	Instance	Returns the child of the `Instance` with the given name. If the child does not exist, it will yield the current thread until it does.

Inherited from Object

Name	Type / Returns	Description
Object:GetPropertyChangedSignal	RBXScriptSignal	Get an event that fires when a given property of the object changes.
Object:IsA	boolean	Returns true if an object's class matches or inherits from a given class.
Object:isA	boolean

Events

Inherited from Instance

Name	Type / Returns	Description
Instance.AncestryChanged		Fires when the `Instance.Parent` property of this object or one of its ancestors is changed.
Instance.AttributeChanged		Fires whenever an attribute is changed on the `Instance`.
Instance.ChildAdded		Fires after an object is parented to this `Instance`.
Instance.childAdded
Instance.ChildRemoved		Fires after a child is removed from this `Instance`.
Instance.DescendantAdded		Fires after a descendant is added to the `Instance`.
Instance.DescendantRemoving		Fires immediately before a descendant of the `Instance` is removed.
Instance.Destroying		Fires immediately before (or is deferred until after) the instance is destroyed via `Instance:Destroy()`.
Instance.StyledPropertiesChanged		Fires whenever any style property is changed on the instance, including when a property is set to `nil`.

Inherited from Object

Name	Type / Returns	Description
Object.Changed		Fires immediately after a property of the object changes, with some limitations.