Format.nvim

format.nvim applies formatting to the current buffer.

Main goals

1. fast
2. async
3. no magic

Deprecated

I am no longer actively maintaining this plugin.
Instead I recommend to use native LSP formatting with mattn/efm-langserver or jose-elias-alvarez/null-ls.nvim.

Or for a non-LSP solution, mhartington/formatter.nvim (for which I am also a maintainer)

Details

format.nvim is a lua plugin and only works in Neovim.

It writes the buffer content into a temporary file, runs user defined commands on that file, then writes the content back into the buffer.

Everything happens asynchronously.

There is no hidden configuration to resolve executables. The commands are run as is. If you need a specific executable, define the path in the command.

By default unsaved changes will not be overwritten, so Format and FormatWrite are safe to call anytime.

Embedded syntax blocks.

format.nvim supports formatting embedded blocks of code with different command than the current filetype. For example lua << EOF blocks in vimscript, or code blocks in markdown. Just specify a start and end-pattern.

Format on save

There is no format on save functionality build in, the plugin only provides the Format and FormatWrite commands. To format on save, you can put this in your vimrc

augroup Format
    autocmd!
    autocmd BufWritePost * FormatWrite
augroup END

Example configuration

Please see :help format.txt for more information on configuration.

require "format".setup {
    ["*"] = {
        {cmd = {"sed -i 's/[ \t]*$//'"}} -- remove trailing whitespace
    },
    vim = {
        {
            cmd = {"luafmt -w replace"},
            start_pattern = "^lua << EOF$",
            end_pattern = "^EOF$"
        }
    },
    vimwiki = {
        {
            cmd = {"prettier -w --parser babel"},
            start_pattern = "^{{{javascript$",
            end_pattern = "^}}}$"
        }
    },
    lua = {
        {
            cmd = {
                function(file)
                    return string.format("luafmt -l %s -w replace %s", vim.bo.textwidth, file)
                end
            }
        }
    },
    go = {
        {
            cmd = {"gofmt -w", "goimports -w"},
            tempfile_postfix = ".tmp"
        }
    },
    javascript = {
        {cmd = {"prettier -w", "./node_modules/.bin/eslint --fix"}}
    },
    markdown = {
        {cmd = {"prettier -w"}},
        {
            cmd = {"black"},
            start_pattern = "^```python$",
            end_pattern = "^```$",
            target = "current"
        }
    }
}

Mentions

At first this was supposed to be a PR to mhartington/formatter.nvim but I ended up rewriting everything.