require

Loads a ModuleScript and returns what it returned.

require runs a ModuleScript the first time you call it and hands back the module's return value. Later calls return the cached value, so the body of a module runs once per script VM, no matter how many scripts require it.

Signature

Call Returns
require(module) whatever the module returned

The argument must be a ModuleScript instance. Passing anything else raises an error.

What a module must do

A module has to return a value. The value can be anything: a table of functions, a single function, a number, or an Instance.

Situation Result
The module returns a value require returns it, and caches it.
The module returns nothing or nil Error: Module 'ReplicatedStorage.MathUtil' did not return anything
Two modules require each other Error: cyclic require of 'ReplicatedStorage.MathUtil'
The module raises an error The error reaches the caller, reported against the module's own path.

The error text uses the instance's full name, which is why the path appears in it.

Example

-- ModuleScript in ReplicatedStorage, named MathUtil
local MathUtil = {}

function MathUtil.clamp(value, low, high)
    return math.max(low, math.min(high, value))
end

return MathUtil

-- Script
local MathUtil = require(game:GetService("ReplicatedStorage").MathUtil)
print(MathUtil.clamp(12, 0, 10))    -- 10

See also