prettier-package-json

Prettier package.json

prettier-package-json is an opinionated JSON formatter inspired by prettier. It removes all original styling and ensures that the outputted package.json conforms to a consistent style.

Usage

Install:

yarn add prettier-package-json --dev

You can install it globally if you like:

yarn global add prettier-package-json

We're defaulting to yarn but you can use npm if you like:

npm install [-g] prettier-package-json

CLI

Run prettier-package-json through the CLI with this script. Run it without any arguments to see the options.

To format a file in-place, use --write. You may want to consider committing your file before doing that, just in case.

prettier-package-json [opts] [filename]

In practice, this may look something like:

prettier-package-json --write ./package.json

Pre-commit hook for changed files

You can use this with a pre-commit tool. This can re-format your files that are marked as "staged" via git add before you commit.

1. lint-staged

Install it along with husky:

yarn add lint-staged husky --dev

and add this config to your package.json:

{
  "scripts": {
    "precommit": "lint-staged"
  },
  "lint-staged": {
    "package.json": [
      "prettier-package-json --write",
      "git add"
    ]
  }
}

See https://github.com/okonet/lint-staged#configuration for more details about how you can configure lint-staged.

2. bash script

Alternately you can just save this script as .git/hooks/pre-commit and give it execute permission:

#!/bin/sh
packagejsonfiles=$(git diff --cached --name-only --diff-filter=ACM | grep 'package\.json$' | tr '\n' ' ')
[ -z "$packagejsonfiles" ] && exit 0

diffs=$(node_modules/.bin/prettier-package-json -l $packagejsonfiles)
[ -z "$diffs" ] && exit 0

echo "here"
echo >&2 "package.json files must be formatted with prettier-package-json. Please run:"
echo >&2 "node_modules/.bin/prettier-package-json --write "$diffs""

exit 1

API

The API has two functions, exported as format and check. format usage is as follows:

const prettier = require("prettier-package-json");

const options = {} // optional
prettier.format(source, options);

check checks to see if the file has been formatted with prettier-package-json given those options and returns a Boolean. This is similar to the --list-different parameter in the CLI and is useful for running in CI scenarios.

Options

Prettier ships with a handful of customizable format options, usable in both the CLI and API.

Option	Default	CLI override	API override
Tab Width - Specify the number of spaces per indentation-level.	2	--tab-width <int>	tabWidth: <int>
Tabs - Indent lines with tabs instead of spaces.	false	--use-tabs	useTabs: <bool>
Key Order - Specify the order of keys.	See default options	--key-order	keyOrder: <comma,separated,list...>

Contributing

See CONTRIBUTING.md.