Module Script

Overview

A ModuleScript is used to structure and separate common functionalities for reuse. It helps reduce code duplication and makes maintenance more efficient.

Recommended Execution Locations

• For modules used by both server and client: It is common to place them in ReplicatedStorage (e.g., referencing a VectorUtil module in both Script and LocalScript).

• For modules used only by the server: For security and management purposes, it is recommended to place them in ServerScriptService (e.g., referencing a ServerGameConstValue module in a Script).

• For modules used only by the client: Depending on the use case, it is recommended to place them in StarterPlayerScripts or StarterCharacterScripts (e.g., referencing a GUI module in a LocalScript).

How It Works

Modules are executed when they are called explicitly (require). The results are cached upon the first call, and subsequent calls return the same value, which enhances execution efficiency and ensures consistency.

1. Implementing a Module Script

local UtilityModule = {}

function UtilityModule.PrintMessage(message)
    print("PrintMessage : " .. message)
end

return UtilityModule

2. Referencing & Using a Module Script

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local UtilityModule = require(ReplicatedStorage.UtilityModule)

UtilityModule:PrintMessage("Hello World!")

Module Script Applications

Utility Class

In ModuleScript

local MathUtil = {}

-- Example Function 1
function MathUtil:Sum(...)
    local numList = { ... }
    local result = 0
    
    for i = 1, #numList do
        result = result + numList[i]
    end
    
    return result 
end

-- Example Function 2
function MathUtil:SomeFunc()
    print("SomeFunc")
end

return MathUtil

In Script or LocalScript

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local MathUtil = require(ReplicatedStorage.MathUtil)

local sum = MathUtil:Sum(1, 5, 9, 10)
print(sum)

Data Class

In ModuleScript

local GameConstValue = {}

GameConstValue.RequirePlayerCount = 10
GameConstValue.MaxRound = 5
GameConstValue.RoundLimitTime = 180

return GameConstValue 

In Script or LocalScript

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local GameConstValue = require(ReplicatedStorage.GameConstValue)

local function CheckPlayerCount(playerCount)
    if playerCount >= GameConstValue.RequirePlayerCount then
        print("Ready to start the game")
    end
end

Class Inheritance

In ModuleScript

local MonsterClass = {}
MonsterClass.__index = MonsterClass

function MonsterClass:new(name, hp, dam, def)
    local self = setmetatable({}, MonsterClass)
    self._Name = name
    self._Hp = hp
    self._MaxHp = hp
    self._Dam = dam
    self._Def = def
    
    return self
end

function MonsterClass:Attack()
    print(self._Name, "Attack!")
end

function MonsterClass:Move()
    print(self._Name, "Move!")
end

function MonsterClass:Destroy()
    print(self._Name, "Destroy!")
end

return MonsterClass

In Script or LocalScript

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local MonsterClass = require(ReplicatedStorage.MonsterClass)

local Goblin = MonsterClass:new("Goblin", 100, 10, 5)
local Orc = MonsterClass:new("Orc", 200, 10, 5)

print(Goblin._Name)
print(Orc._Name)

Goblin:Attack()
Orc:Attack()