How to set up Neoformat to format on save in Neovim?

Add an autocmd to your vimrc: `autocmd BufWritePre * undojoin | Neoformat`. This formats on save and uses undojoin to properly manage undo history, as explained in the README's Managing Undo History section.

Neoformat vs ale for code formatting, which should I use?

Neoformat is specialized for formatting with a wide range of external tools, while ale is a linting engine that can format but often with fewer formatter options. Choose Neoformat if you need dedicated, multi-formatter support across many languages.

Why is Neoformat not working with my prettier installation?

Ensure prettier is installed globally or in node_modules, and check that the formatter configuration has stdin set to 1 if supported. Also, verify the filetype is enabled in g:neoformat_enabled lists.

How to add a custom formatter not listed in Neoformat?

Create a Vimscript file in autoload/neoformat/formatters/ with functions defining the exe, args, and other options, following the template provided in the README's Adding a New Formatter section.

Does Neoformat support format on type or only on command?

Neoformat runs on command or via autocmds; it doesn't natively support format-as-you-type. However, you can bind it to keystrokes or use plugins to simulate real-time formatting.

How to configure Neoformat to use black for Python instead of autopep8?

Set `let g:neoformat_enabled_python = ['black']` in your vimrc and ensure black is installed. You can also define custom settings in g:neoformat_python_black if needed for arguments or environment variables.

neoformat — Neovim Code Formatter Plugin

What is neoformat?

Neoformat is a (Neo)vim plugin that automatically formats code by interfacing with external code formatters for a wide variety of programming languages and file types. It solves the problem of inconsistent code styling by providing a single command to format buffers without saving files first, integrating seamlessly into the editor workflow.

Target Audience

Vim and Neovim users who want automated code formatting across multiple languages without leaving their editor, particularly developers working in polyglot codebases.

Value Proposition

Developers choose Neoformat for its extensive formatter support, buffer-based operation that avoids file saves, and its ability to maintain editor state, offering a more integrated and reliable formatting experience compared to manual formatter invocations.

Overview

:sparkles: A (Neo)vim plugin for formatting code.

Use Cases

Best For

Automatically formatting code in Vim/Neovim across dozens of languages with a single plugin
Integrating multiple code formatters (like Prettier, Black, gofmt) into a unified editor workflow
Formatting code without saving the file first to preserve unsaved changes
Maintaining editor state (marks, jumps) after running code formatters
Configuring custom formatters with specific arguments and environment variables
Setting up format-on-save functionality for consistent code style

Not Ideal For

Environments where writing to /tmp is restricted, such as sandboxed containers or security-focused systems
Teams seeking a zero-configuration formatting solution without managing external formatter installations
Projects requiring real-time, as-you-type formatting integrated with language servers or other IDE features

Pros & Cons

Pros

Extensive Formatter Support

Supports over 70 filetypes with multiple external formatters like Prettier, Black, and gofmt, as detailed in the lengthy README list.

Buffer-Based Operation

Uses getbufline() to format code directly from the buffer without requiring a file save, preserving unsaved changes.

State Preservation

Maintains marks, jumps, and undo history after formatting by using setline(), ensuring a seamless editing experience.

Configurable Fallbacks

Allows defining multiple formatters per filetype and tries them sequentially until one succeeds, reducing formatting failures.

Cons

External Dependency Burden

Requires each external formatter (e.g., prettier, black) to be installed and configured separately, adding significant setup overhead.

Complex Configuration

Setting up custom formatters involves defining variables with numerous options like exe, args, and stdin, which can be overwhelming and error-prone.

File System Reliance

Formatters that don't support stdin write buffer data to /tmp/neoformat/, which may fail in environments with restricted file access or cleanup policies.

neoformat

What is neoformat?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

neoformat

What is neoformat?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?