configuring air lsp/formatter

lsp.lua

-- After installing air, configure it like this
local configs = require("lspconfig.configs")
configs.air = {
    default_config = {
        cmd = { vim.fn.expand("$HOME/.local/bin/air"), "language-server" },
        filetypes = { "r" },
        root_dir = function(fname)
            local git_dir = vim.fs.find(".git", { path = fname, upward = true })[1]
            return git_dir and vim.fs.dirname(git_dir) or vim.loop.os_homedir()
        end,
        settings = {},
    },
}

-- Then, to format on save, you can use something like this in /after/lsp.lua
vim.api.nvim_create_autocmd("BufWritePre", {
    pattern = { "*.R", "*.r" },
    callback = function()
        vim.lsp.buf.format({
            async = true,
            filter = function(client)
                return client.name == "air"
            end,
        })
    end,
})