nvim/lua/plugins/lint.lua

-- Stolen from LazyVim https://github.com/LazyVim/LazyVim/tree/f086bcde253c29be9a2b9c90b413a516f5d5a3b2/lua/lazyvim/plugins
return {
	"mfussenegger/nvim-lint",
	event = { "VeryLazy", "BufWritePost", "BufReadPost", "InsertLeave" },
	opts = {
		-- Event to trigger linters
		events = { "BufWritePost", "BufReadPost", "InsertLeave", "CursorHold", "CursorHoldI" },
		linters_by_ft = {
			-- Builtin: https://github.com/mfussenegger/nvim-lint/tree/master/lua/lint/linters
			markdown = { "markdownlint" },
			-- lua = { "luacheck" }, -- TODO revisit this was not working last time
			typescript = { "biomejs" },
			typescriptreact = { "biomejs" },
			javascript = { "biomejs" },
			javascriptreact = { "biomejs" },
			-- Use the "*" filetype to run linters on all filetypes.
			-- ['*'] = { 'global linter' },
			-- Use the "_" filetype to run linters on filetypes that don't have other linters configured.
			-- ['_'] = { 'fallback linter' },
			-- ["*"] = { "typos" },
		},
		-- LazyVim extension to easily override linter options
		-- or add custom linters.
		---@type table<string,table>
		--
		-- Options:
		-- cmd = 'linter_cmd',
		-- stdin = true, -- or false if it doesn't support content input via stdin. In that case the filename is automatically added to the arguments.
		-- append_fname = true, -- Automatically append the file name to `args` if `stdin = false` (default: true)
		-- args = {}, -- list of arguments. Can contain functions with zero arguments that will be evaluated once the linter is used.
		-- stream = nil, -- ('stdout' | 'stderr' | 'both') configure the stream to which the linter outputs the linting result.
		-- ignore_exitcode = false, -- set this to true if the linter exits with a code != 0 and that's considered normal.
		-- env = nil, -- custom environment table to use with the external process. Note that this replaces the *entire* environment, it is not additive.
		-- parser = your_parse_function
		--
		-- your_parse_function can be a function which takes three arguments:
		--     output
		--     bufnr
		--     linter_cwd
		-- The output is the output generated by the linter command. The function must return a list of diagnostics as specified in :help diagnostic-structure.
		linters = {
			luacheck = {
				args = {
					"--globals",
					"vim",
					"--globals",
					"NIX",
					"--globals",
					"U",
					"--max_line_length",
					"240",
					"--max_code_line_length",
					"240",
					"--max_string_line_length",
					"240",
					"--max_comment_line_length",
					"240",
					"--formatter",
					"plain",
					"--codes",
					"--ranges",
					"-",
				},
			},
			-- TODO add v vet? for v-lang?
			-- -- Example of using selene only when a selene.toml file is present
			-- selene = {
			--   -- `condition` is another LazyVim extension that allows you to
			--   -- dynamically enable/disable linters based on the context.
			--   condition = function(ctx)
			--     return vim.fs.find({ "selene.toml" }, { path = ctx.filename, upward = true })[1]
			--   end,
			-- },
		},
	},
	config = function(_, opts)
		local M = {}

		local lint = require("lint")
		for name, linter in pairs(opts.linters) do
			if type(linter) == "table" and type(lint.linters[name]) == "table" then
				lint.linters[name] = vim.tbl_deep_extend("force", lint.linters[name], linter)
			else
				lint.linters[name] = linter
			end
		end
		lint.linters_by_ft = opts.linters_by_ft

		function M.debounce(ms, fn)
			local timer = vim.uv.new_timer()
			return function(...)
				local argv = { ... }
				timer:start(ms, 0, function()
					timer:stop()
					vim.schedule_wrap(fn)(unpack(argv))
				end)
			end
		end

		function M.lint()
			-- Use nvim-lint's logic first:
			-- * checks if linters exist for the full filetype first
			-- * otherwise will split filetype by "." and add all those linters
			-- * this differs from conform.nvim which only uses the first filetype that has a formatter
			local names = lint._resolve_linter_by_ft(vim.bo.filetype)

			-- Create a copy of the names table to avoid modifying the original.
			names = vim.list_extend({}, names)

			-- Add fallback linters.
			if #names == 0 then
				vim.list_extend(names, lint.linters_by_ft["_"] or {})
			end

			-- Add global linters.
			vim.list_extend(names, lint.linters_by_ft["*"] or {})

			-- Filter out linters that don't exist or don't match the condition.
			local ctx = { filename = vim.api.nvim_buf_get_name(0) }
			ctx.dirname = vim.fn.fnamemodify(ctx.filename, ":h")
			names = vim.tbl_filter(function(name)
				local linter = lint.linters[name]
				if not linter then
					LazyVim.warn("Linter not found: " .. name, { title = "nvim-lint" })
				end
				return linter and not (type(linter) == "table" and linter.condition and not linter.condition(ctx))
			end, names)

			-- Run linters.
			if #names > 0 then
				lint.try_lint(names)
			end
		end

		vim.api.nvim_create_autocmd(opts.events, {
			group = vim.api.nvim_create_augroup("nvim-lint", { clear = true }),
			callback = M.debounce(100, M.lint),
		})
	end,
}