:vim.lsp.buf.formatting() or vim.lsp.buf.formatting_sync()<\/code> (in nvim v 0.8, vim.lsp.buf.format<\/code>) will not work. For them to work, you need to install an external formatter called shfmt<\/a> and hook (merge) shfmt<\/code> into Neovim LSP client by using 1-2 lines of configuration (I will show you that below). Now, the nvim’s above formatting commands will format your code.<\/p>\n\n\n\nSimilarly, I was able to hook Diagnostics<\/a> and Code-Actions<\/a> into the Neovim client using shellcheck<\/a>.<\/p>\n\n\n\nUsing null-ls, you can hook not only formatting, code actions, and diagnostics, but the following services as well:<\/p>\n\n\n\n
\n- Hover<\/li>\n\n\n\n
- Completion<\/li>\n<\/ul>\n\n\n\n
Table of Contents<\/h2>\n\n\n\n\n- Install null-ls and other packages and configure them<\/a><\/li>\n\n\n\n
- Formatting in null-ls<\/a>\n
\n- Test if the above formatting configuration in null-ls is working<\/a><\/li>\n\n\n\n
- Keybindings for nvim-lsp formatting<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Diagnostics (linting) in null-ls<\/a><\/li>\n\n\n\n
- Code actions in null-ls<\/a><\/li>\n\n\n\n
- Way Ahead<\/a><\/li>\n<\/ul>\n\n\n\n
Install null-ls and other packages and configure them<\/h2>\n\n\n\n
First of all, install the null-ls plugin using your favorite plugin manager.<\/p>\n\n\n\n
For example, to install using vim-plug*, use the following command in init.vim<\/code>:<\/p>\n\n\n\nPlug 'jose-elias-alvarez\/null-ls.nvim'<\/code><\/pre>\n\n\n\n*Head on over to this article for a detailed and easy guide on managing plugins using vim-plug.<\/a><\/p>\n\n\n\nFor this article, I will be using bash-language-server, shfmt, and shellcheck as examples. So, kindly install them as well using your distributions’ package managers:<\/p>\n\n\n\n
Using snap<\/strong><\/p>\n\n\n\nsudo snap install bash-language-server<\/code><\/pre>\n\n\n\nOn Debian-based distros<\/strong>:<\/p>\n\n\n\nsudo apt install shellcheck<\/code><\/pre>\n\n\n\nOn Fedora-based distributions<\/strong><\/p>\n\n\n\ndnf install -y nodejs-bash-language-server\ndnf install shellcheck<\/code><\/pre>\n\n\n\nFor Arch Linux, Manjaro, and other Arch Linux-based distributions<\/strong><\/p>\n\n\n\nsudo pacman -S bash-language-server shfmt shellcheck<\/code><\/pre>\n\n\n\nIf the above does not cover your distributions\/OSes, head over to the official websites of these packages or search on Google and install them from there. However, always prefer your distributions\/OSes’ package managers because of the ease in the update\/install\/uninstall.<\/p>\n\n\n\n
Please set up your bash-language-server if you have not done it. You can follow my article on this nvim-lsp setup<\/a>.<\/p>\n\n\n\nFormatting in null-ls<\/h2>\n\n\n\n
Format-commands in nvim-lsp remove\/insert unnecessary tabs\/spaces in your code. Therefore, it beautifies it. <\/p>\n\n\n\n
To know more about it, look at my article on formatting in nvim-lsp<\/a>.<\/p>\n\n\n\nAs foretold, for the bash-language-server, the nvim’s formatting commands :vim.lsp.buf.formatting() or vim.lsp.buf.formatting_sync()<\/code> (in nvim v 0.8, vim.lsp.buf.format<\/code>) will not have any effect.<\/p>\n\n\n\nTo make them work, first create a file ~\/.config\/nvim\/plug-config\/null-ls.lua<\/code>. In this file, you will be populating all of your plugin-related configurations. You could throw all of your configurations in the init.vim<\/code> or init.lua<\/code> instead but that will be quite a messy configuration. So, I am creating a separate file. Later, I will show you how this file can be “sourced” into the init.vim<\/code> using the source<\/code> command.<\/p>\n\n\n\nAfter creating the file put the following configuration into it:<\/p>\n\n\n\n
require(\"null-ls\").setup({\n sources = {\n require(\"null-ls\").builtins.formatting.shfmt, -- shell script formatting\n },\n})<\/code><\/pre>\n\n\n\nIn the above configuration, I am using the “source” shfmt<\/code>. To find other supported sources, head over to the list of supported sources<\/a> on the official website.<\/p>\n\n\n\nOr, execute the nvim command :NullLsInfo<\/code>.<\/p>\n\n\n\n![\"NullLsInfo](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/07\/nulllsinfo-command.png?resize=731%2C458&ssl=1\")
Figure: :NullLsInfo<\/code> shows you supported sources for the given filetype in a floating window<\/figcaption><\/figure>\n\n\n\nIt will be a good practice to bind a key to the above command. For this, you can append the following line in the file ~\/.config\/nvim\/plug-config\/null-ls.lua<\/code>:<\/p>\n\n\n\nvim.cmd('map <Leader>ln :NullLsInfo<CR>')<\/code><\/pre>\n\n\n\nThe above formatting configuration was for sh<\/code> file type. For other filetypes, follow the similar procedure.<\/p>\n\n\n\nFor example, for markdown formatting, open a markdown file, and execute the :NullLsInfo<\/code> command, it will show you supported formatting sources. If you like to use the source prettier<\/code>, use the prettier<\/code> line in sources = {}<\/code> in the following fashion:<\/p>\n\n\n\nrequire(\"null-ls\").setup({\n sources = {\n require(\"null-ls\").builtins.formatting.shfmt, -- shell script formatting\n require(\"null-ls\").builtins.formatting.prettier, -- markdown formatting\n },\n})<\/code><\/pre>\n\n\n\nTest if the above formatting configuration in null-ls is working<\/h3>\n\n\n\n
Now as a test, go ahead and destroy the formatting of one of your shell scripts<\/a> by inserting unnecessary tabs and spaces. Now, execute the nvim formatting command. You will see the removal of unnecessary tabs and spaces.<\/p>\n\n\n\nI will recommend you bind the formatting commands with some key(s) as shown below.<\/p>\n\n\n\n
Keybindings for nvim-lsp formatting<\/h3>\n\n\n\n
Append the following lines to the file ~\/.config\/nvim\/plug-config\/null-ls.lua<\/code>:<\/p>\n\n\n\nvim.cmd('map <Leader>lf :lua vim.lsp.buf.formatting_sync(nil, 10000)<CR>')<\/code><\/pre>\n\n\n\nIf you get timeout<\/code> error on executing the above shortcut, which might happen on a long file, increase the number. 10000<\/code> is already a very big number, so the error is highly unlikely.<\/p>\n\n\n\nNote 1:<\/strong> Please note that the formatting command is a little different in nvim v 0.8:<\/p>\n\n\n\n-- 0.7\nvim.lsp.buf.formatting_sync(nil, 2000) -- 2 seconds\n\n-- 0.8\nvim.lsp.buf.format({ timeout_ms = 2000 }) -- 2 seconds<\/code><\/pre>\n\n\n\nNote 2:<\/strong> If you already have bound key(s) for the formatting command(s), there is no need to rebind using the above method.<\/p>\n\n\n\nSome sources (but not the shfmt<\/code>) support range formatting as well. For this, append the following line in the file ~\/.config\/nvim\/plug-config\/null-ls.lua<\/code>:<\/p>\n\n\n\nvim.cmd('map <Leader>lF :lua vim.lsp.buf.range_formatting()<CR>')<\/code><\/pre>\n\n\n\nNow, you can visually select the lines (using the standard vim key Shift+v<\/code>) on which you want to apply the formatting and press the shortcut key. The Rest of the lines will be untouched.<\/p>\n\n\n\nDiagnostics (linting) in null-ls<\/h2>\n\n\n\n
Nvim lsp diagnostics (also known as \u201clinting\u201d) enables you to see Errors, Warnings, Hints, and information right on your screen while coding<\/strong>. It, therefore, prevents you from having most of the debugging headaches later.<\/p>\n\n\n\nTo know more about it, head over to my article on diagnostics in nvim-lsp<\/a>.<\/p>\n\n\n\n![\"Diagnostics](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/05\/1.jpg?resize=1051%2C652&ssl=1\")
Figure: Diagnostics in bash-language-server pulled from shellcheck<\/figcaption><\/figure>\n\n\n\nBy default, the bash-language-server server does not provide diagnostics services.<\/p>\n\n\n\n
Now, to get the diagnostics enabled use the following code in your file ~\/.config\/nvim\/plug-config\/null-ls.lua<\/code>:<\/p>\n\n\n\nrequire(\"null-ls\").setup({\n sources = {\n require(\"null-ls\").builtins.formatting.shfmt, -- shell script formatting\n require(\"null-ls\").builtins.formatting.prettier, -- markdown formatting\n require(\"null-ls\").builtins.diagnostics.shellcheck, -- shell script diagnostics\n },\n})<\/code><\/pre>\n\n\n\nJust add the shellcheck<\/code> line from the above code in the file. There is no need to repeat\/remove other configurations from the file.<\/p>\n\n\n\nNow, open a shell script and you will see diagnostics printed on your terminal.<\/p>\n\n\n\n
Note<\/strong>: with the recent update of bash-language-server, you don’t have to follow this heading. Now, bash-language-server uses the shellcheck if installed for the linting. Nonetheless, this method is still useful for other scenarios.<\/p>\n\n\n\nCode actions in null-ls<\/h2>\n\n\n\n
Diagnostics show you the errors and warnings in your code. On the other hand, code actions<\/a> are available suggestions to fix\/remove these errors and warnings. Not all language servers provide this service. To fill this gap, you can use null-ls.<\/p>\n\n\n\n![\"code](\"https:\/\/i0.wp.com\/smarttech101.com\/wp-content\/uploads\/2022\/06\/nvim-lsp-code-action.png?resize=731%2C458&ssl=1\")
Figure: code actions in nvim-lsp (shown at the bottom) from shellcheck<\/figcaption><\/figure>\n\n\n\nTo hook code actions from shellcheck into the neovim client, insert the line require(\"null-ls\").builtins.code_actions.shellcheck,<\/code> in the file ~\/.config\/nvim\/plug-config\/null-ls.lua<\/code> in the following fashion:<\/p>\n\n\n\nrequire(\"null-ls\").setup({\n sources = {\n require(\"null-ls\").builtins.formatting.shfmt, -- shell script formatting\n require(\"null-ls\").builtins.formatting.prettier, -- markdown formatting\n require(\"null-ls\").builtins.diagnostics.shellcheck, -- shell script diagnostics\n require(\"null-ls\").builtins.code_actions.shellcheck, -- shell script code actions\n },\n})<\/code><\/pre>\n\n\n\nWay Ahead<\/h2>\n\n\n\n
To use other null-ls features such as “Hover” (example – on hovering on a word, you would get its meaning; it is good for language learners), how to create a source, etc. see the official null-ls documentation<\/a><\/p>\n\n\n\n