prettier-plugin-sort-json

prettier-plugin-sort-json

A plugin for Prettier that sorts JSON files by property name.

[!IMPORTANT] This plugin supports Prettier v3 as of version 3.0.0 of this plugin. The latest release will no longer work with Prettier v2.

We are maintaining support for Prettier v2 on version 2 of this plugin. See the main-v2 branch for instructions on using v2 of this plugin.

Requirements

This module requires an LTS Node version (v16.0.0+), and prettier v3+.

Install

Using npm:

npm install --save-dev prettier-plugin-sort-json

Using yarn:

yarn add --dev prettier-plugin-sort-json

Then follow these instructions to load the plugin.

There are some additional configuration options available (described below), but they are all optional.

Description

This plugin adds a JSON preprocessor that will sort JSON files alphanumerically by key. By default, only top-level JSON objects are sorted. JSON files containing Arrays or other non-Object values are skipped.

Object entries are sorted by key lexically using Array.sort, according to each character's Unicode code point value.

Note that this will not sort package.json, package-lock.json, or composer.json. This plugin only affects the json parser used by Prettier. Prettier uses an alternate parser (json-stringify) for those three specific files (See here for details).

This also will not sort JSON objects within other types of files, such as JavaScript or TypeScript files. This is just for sorting JSON files.

Examples

Before:

{
  "z": null,
  "a": null,
  "b": null,
  "0": null,
  "exampleNestedObject": {
    "z": null,
    "a": null
  }
}

After:

{
  "0": null,
  "a": null,
  "b": null,
  "exampleNestedObject": {
    "z": null,
    "a": null
  },
  "z": null
}

Configuration

These configuration options are all optional. Each option can be set as a CLI flag, or as an entry in your Prettier configuraton (e.g. in your .prettierrc file).

JSON Recursive Sort

Sort JSON objects recursively, including all nested objects. This also sorts objects within JSON arrays.

Default	CLI	Configuration
false	--json-recursive-sort	jsonRecursiveSort: <bool>

JSON Sort Order

Use a custom sort order. This is specified as a JSON string that maps exact strings or regular expressions to sorting algorithms.

Default	CLI	Configuration
""	--json-sort-order '<string>'	jsonSortOrder: <string>

Here is an example JSON sort order string:

'{ "placeThisFirst": null, "/^[^\\d+]/": "lexical", "/^\\d+/": "numeric" }'

This sorts the key "placeThisFirst" ahead of all others. After that, the set of all keys that don't start with a number are sorted lexically. Lastly, the set of keys that start with a number are sorted numerically.

Each key represents a literal key value or a category of keys, represented by a regular expression. Regular expressions are identified by leading and trailing forward slashes, along with some number of paths optionally following the trailing slash (supported flags are i, m, s, and u).

Each category is ordered in relation to other categories. Each value represents the sorting algorithm to use within that category. If the value is null, the default sorting algorithm lexical is used. Here are the supported sorting algorithms:

Sorting Algorithm	Description
lexical	Sort lexically (i.e. lexicographically). This is the default.
numeric	For keys that are prefixed with a number, sort by that number in ascending order. Otherwise sort lexically.
reverseLexical	Reverse-order lexical sort.
reverseNumeric	Reverse-order numeric sort.
caseInsensitiveLexical	Case-insensitive lexical sort.
caseInsensitiveNumeric	Case-insensitive numeric sort.
caseInsensitiveReverseLexical	Case-insensitive reverse-order lexical sort.
caseInsensitiveReverseNumeric	Case-insensitive reverse-order numeric sort.
none	Do not sort.

Keys that do not match any defined category are treated as being in an implied last category, with lexical sorting.

Note: Escaping can be tricky, especially if you are using regular expression sort keys. These regular expressions are configured as strings, so any backslashes require an additional escape (e.g. notice the double-backslash here: "/^\\d+/").

If this key is configured as part of a JSON Prettier configuration file (prettierrc.json), all double-quotes and backslashes need to be escaped again. For example, the example JSON sort order string would would be "{ \"placeThisFirst\": null, \"/^[^\\\\d+]/\": \"lexical\", \"/^\\\\d+/\": \"numeric\" }.

Contributing

Setup

• Install the current LTS version of Node.js
  • If you are using nvm (recommended) running nvm use will automatically choose the right node version for you.
• Install Yarn v3
• Run yarn install to install dependencies and run any requried post-install scripts

Testing and Linting

Run yarn test to run the tests.

Run yarn lint to run the linter, or run yarn lint:fix to run the linter and fix any automatically fixable issues.

Release & Publishing

The project follows the same release process as the other libraries in the MetaMask organization. The GitHub Actions action-create-release-pr and action-publish-release are used to automate the release process; see those repositories for more information about how they work.

1. Choose a release version.

   • The release version should be chosen according to SemVer. Analyze the changes to see whether they include any breaking changes, new features, or deprecations, then choose the appropriate SemVer version. See the SemVer specification for more information.

2. If this release is backporting changes onto a previous release, then ensure there is a major version branch for that version (e.g. 1.x for a v1 backport release).

   • The major version branch should be set to the most recent release with that major version. For example, when backporting a v1.0.2 release, you'd want to ensure there was a 1.x branch that was set to the v1.0.1 tag.

3. Trigger the workflow_dispatch event manually for the Create Release Pull Request action to create the release PR.

   • For a backport release, the base branch should be the major version branch that you ensured existed in step 2. For a normal release, the base branch should be the main branch for that repository (which should be the default value).
   • This should trigger the action-create-release-pr workflow to create the release PR.

4. Update the changelog to move each change entry into the appropriate change category (See here for the full list of change categories, and the correct ordering), and edit them to be more easily understood by users of the package.

   • Generally any changes that don't affect consumers of the package (e.g. lockfile changes or development environment changes) are omitted. Exceptions may be made for changes that might be of interest despite not having an effect upon the published package (e.g. major test improvements, security improvements, improved documentation, etc.).
   • Try to explain each change in terms that users of the package would understand (e.g. avoid referencing internal variables/concepts).
   • Consolidate related changes into one change entry if it makes it easier to explain.
   • Run yarn auto-changelog validate --rc to check that the changelog is correctly formatted.

5. Review and QA the release.

   • If changes are made to the base branch, the release branch will need to be updated with these changes and review/QA will need to restart again. As such, it's probably best to avoid merging other PRs into the base branch while review is underway.

6. Squash & Merge the release.

   • This should trigger the action-publish-release workflow to tag the final release commit and publish the release on GitHub.

7. Publish the release on npm.

   • Be very careful to use a clean local environment to publish the release, and follow exactly the same steps used during CI.
   • Use npm publish --dry-run to examine the release contents to ensure the correct files are included. Compare to previous releases if necessary (e.g. using https://unpkg.com/browse/[package name]@[package version]/).
   • Once you are confident the release contents are correct, publish the release using npm publish.

Changelog

[4.0.0]

Changed

• BREAKING: Drop support for Node.js v16 (#203)
• BREAKING: Update case insensitive sort to use deterministic key order (#189)
  • Previously the "case insensitive" sorting options would leave keys in their original order when they differed only in case. They have been updated to sort identical keys in case order instead, making these sort options deterministic.
  • This change has been made because deterministic sort orders tend to be easier to work with, are more aligned with how Prettier works, and typically lead to less churn. However, if your project needs to preserve original key order, you can emulate the old behavior by defining a custom sort order that has a category for each case-insensitive character. For example, you could set this as your prettierrc.js file:

    {
        jsonSortOrder: JSON.stringify({
            '/^[Aa]/': 'none',
            '/^[Bb]/': 'none',
            '/^[Cc]/': 'none',
            ...
            '/^[Zz]/': 'none',
        })
    }
  

  This should work for small character sets. If you require case-insensitive sorting with a larger character set, please submit a feature request. We can bring back the old sorting order as an option if there is demand for it.