Lua Code Formatter

Lua code and StyLua

Lua turns up wherever a program needs a small embedded scripting language: Neovim and WezTerm configuration, LÖVE and Defold games, Roblox, World of Warcraft addons, Redis EVAL scripts, Nginx through OpenResty, and HAProxy. Its syntax is loose enough that hand-written files drift quickly, with statements packed onto one line, mixed quote styles and inconsistent indentation.

StyLua is an opinionated Lua formatter written in Rust and modelled on Prettier: it parses the file and prints it again from the syntax tree, so the result is the same however messy the input was. It is especially common among Neovim plugin authors, and many plugin repositories check formatting with it in CI. Here it runs as WebAssembly inside the page; your scripts are never sent to a server.

What StyLua changes

• One statement per line. local a=1 local b=2 becomes two lines, and if not ok then return end is expanded into a three-line block.
• Spacing. Spaces go around operators and after commas, and table constructors get padding: {a=1} becomes { a = 1 }.
• Quotes. Strings prefer double quotes, so 'hello' becomes "hello". A string that would need escapes keeps the quote that avoids them, so 'say "hi"' is left alone. Long bracket strings like [[ ... ]] are never touched.
• Call parentheses. Lua lets you call a function with a single string or table argument and no parentheses. StyLua adds them, so require 'socket' becomes require("socket") and setup{...} becomes setup({...}).
• Line wrapping. Long calls and tables are broken over several lines at 80 columns. Anonymous functions passed as arguments, such as the callback in vim.keymap.set, keep the function() on the call line and close with end, {...}).

Comments are kept in place and require calls stay in the order you wrote them. For a Redis EVAL script, paste the Lua body itself rather than the whole redis-cli command, whose shell quoting is not Lua. To protect a hand-aligned table, put -- stylua: ignore on the line before a statement, or wrap a region in -- stylua: ignore start and -- stylua: ignore end.

Indentation and language versions

There are no Lua-specific options. The toolbar’s Indent decides between 2 spaces, 4 spaces and tabs. StyLua’s own default is tabs, while most Neovim configs use 2 spaces, so match whatever the rest of your repository uses. Lines are wrapped at 80 columns rather than StyLua’s usual 120, and StyLua treats that width as a target rather than a hard cap, so an unbreakable long string can still run past it. StyLua runs on Ctrl/Cmd+Enter, and Ctrl/Cmd+Shift+C copies.

The parser accepts Lua 5.1 through 5.4, which covers LuaJIT as well: goto and ::labels::, integer division //, bitwise operators and <const> and <close> attributes all work. Luau, the Roblox dialect, is only partly supported. A .luau file formats if it sticks to standard Lua, but type annotations such as a: number, type declarations, continue and compound assignments like x += 1 fail with a parse error.

Examples

vim.keymap.set('n','<leader>ff',function() require('telescope.builtin').find_files({hidden=true}) end,{desc='Find files'})
vim.opt.number=true vim.opt.relativenumber=true vim.opt.tabstop=4
vim.api.nvim_create_autocmd('BufWritePre',{pattern='*.lua',callback=function() vim.lsp.buf.format() end})

vim.keymap.set("n", "<leader>ff", function()
  require("telescope.builtin").find_files({ hidden = true })
end, { desc = "Find files" })
vim.opt.number = true
vim.opt.relativenumber = true
vim.opt.tabstop = 4
vim.api.nvim_create_autocmd("BufWritePre", {
  pattern = "*.lua",
  callback = function()
    vim.lsp.buf.format()
  end,
})

local Inventory={} Inventory.__index=Inventory
function Inventory.new(items) local self=setmetatable({},Inventory) self.items=items or {} return self end
function Inventory:total() local t=0 for _,item in ipairs(self.items) do if item.qty>0 then t=t+item.qty*item.price end end return t end
local inv=Inventory.new({{sku="KB-104",qty=1,price=129.9},{sku="MS-220",qty=2,price=39.5}})
print(string.format("total: %.2f",inv:total()))

local Inventory = {}
Inventory.__index = Inventory
function Inventory.new(items)
	local self = setmetatable({}, Inventory)
	self.items = items or {}
	return self
end
function Inventory:total()
	local t = 0
	for _, item in ipairs(self.items) do
		if item.qty > 0 then
			t = t + item.qty * item.price
		end
	end
	return t
end
local inv = Inventory.new({
	{ sku = "KB-104", qty = 1, price = 129.9 },
	{ sku = "MS-220", qty = 2, price = 39.5 },
})
print(string.format("total: %.2f", inv:total()))

local player={x=100,y=200,speed=180}
function love.load() love.window.setTitle 'Orbit' font=love.graphics.newFont(14) end
function love.update(dt) if love.keyboard.isDown('right') then player.x=player.x+player.speed*dt end end
function love.draw() love.graphics.print('Score: '..score,10,10) love.graphics.circle('fill',player.x,player.y,12) end

local player = { x = 100, y = 200, speed = 180 }
function love.load()
    love.window.setTitle("Orbit")
    font = love.graphics.newFont(14)
end
function love.update(dt)
    if love.keyboard.isDown("right") then
        player.x = player.x + player.speed * dt
    end
end
function love.draw()
    love.graphics.print("Score: " .. score, 10, 10)
    love.graphics.circle("fill", player.x, player.y, 12)
end

Common errors and how to fix them

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