prettier-detect

prettier-detect

A CLI tool to figure out the least disruptive Prettier config to add to an existing project.

[!WARNING]

This project was just a quick exploration of an idea. It's shared as a curiosity and won't be actively maintained or improved.

Overview

Sometimes you wind up in an unfamiliar repository, without a formatter in sight and where every ⌘-s triggers auto formatting, seeding noise and despair in the next commit's diff.

You want to throw in some kind of formatter to take the edge off this, but you don't want to spend time reverse-engineering the stylistic proclivities of the author into a do-no-harm .prettierrc file.

The prettier-detect CLI tool helps out here, by fuzzing through Prettier config combinations to find the configuration that minimizes the size of the post-format diff.

Useful for random forks, useful for projects that are late to adopt formatters.

Getting started

Dependencies

Prettier detect requires Node 18+. The exported APIs are ESM-only and share the Node 18+ requirement. You'll also need a git binary somewhere in your path.

Installation

Invoke directly:

npx prettier-detect

Or, install globally for access across your system:

npm install --global prettier-detect

Usage

Just run prettier-detect in the repo in question, redirecting the output if you'd like to save it straight to a config file:

prettier-detect ./ > .prettierrc.json

It can take a while to run on large repos. It's trying a lot of combinations.

Default configuration values are remove by default.

CLI

Command: prettier-detect

Get the least disruptive Prettier config to add to an existing project.

Usage:

prettier-detect <directory>

Positional Argument	Description	Type
directory	Directory to evaluate.	string

Option	Description	Type	Default
--strip	Strip any discovered configuration values that match Prettier's defaults.	boolean	true
--strategy	How to search the possibility space. "fuzz" brute-forces config permutations, "popular" tests the most common Prettier configs found in popular GitHub repositories.	"popular" "fuzz"	"popular"
--verbose	Enable verbose logging. All verbose logs and prefixed with their log level and are printed to stderr for ease of redirection.	boolean	false
--help -h	Show help	boolean
--version -v	Show version number	boolean

API

A single function is exported, which works just like the CLI tool, except it returns a Prettier configuration options object instead of.

export async function detectConfig(
  path: string,
  strip = true,
  verbose = false,
): Promise<PrettierOptions>

License

MIT © Eric Mika