Luau comments

A comment is text that the Luau parser ignores at runtime.

Single-line comments

You can define single-line comments with a double hyphen (--) anywhere outside a string. Single-line comments extend to the end of the line.

Use single line comments for in-line notes. If the comment spans multiple lines, use multiple single-line comments.

You can add and remove single-line comments in the Script Editor with the keyboard shortcut Ctrl/ (⌘/).

-- This condition is really important because the world would blow up if it
-- were missing.
if not foo then
	stopWorldFromBlowingUp()
end

Block comments

You can define multiline block comments with double hyphens and double brackets (--[[]]). Use block comments for documenting items:

• Use a block comment at the top of files to describe their purpose.
• Use a block comment before functions or objects to describe their intent.

--[[
    Shuts off the cosmic moon ray immediately.

    Should only be called within 15 minutes of midnight Mountain Standard
    Time, or the cosmic moon ray may be damaged.
]]
local function stopCosmicMoonRay()
end

If necessary, you can nest multiple brackets inside a block comment using the same number of equal signs in both the beginning and ending bracket:

--[=[
    In-depth detail about cosmic moon ray: [[[TOP SECRET]]]
]=]

Comment directives

Luau uses comments that start with ! to control features like type checking, native code generation, and linting.

--!strict
--!nonstrict
--!nocheck
--!native
--!nolint
--!optimize 0|1|2

For linting, Roblox Studio enables the following subset of warning codes from the Luau linter: 1, 2, 3, 6, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28.

The --!optimize directive controls the optimization level of the Luau compiler for the script:

• 0 disables optimizations.
• 1 enables basic optimizations (default in Studio testing).
• 2 enables further optimizations (default in live games).

Exact optimizations aren't published and are subject to change. We recommend using the default values unless you have a specific reason not to.

To-do comments

Roblox Studio supports special TODO comments. Studio bolds any text following TODO (until broken by a space):

-- TODO: Finish the function below so that it actually does what its name implies.
local function stopWorldFromBlowingUp()
end

Use TODO comments to keep track of and communicate issues within your code.