Prettier Plugin Expand JSON

1.0.4 verified Sat Apr 25 auth: no javascript

Prettier plugin that expands all JSON arrays and objects into multi-line format, ensuring consistent formatting for JSON and JSONC files. Current stable version 1.0.4, released with no dependencies. Engine requires Node >=20. Unlike default Prettier behavior which may collapse short objects, this plugin always forces multi-line output. Works with special files like package.json and composer.json, and can be combined with other JSON plugins (must be listed last).

Common errors

error Cannot find module 'prettier-plugin-expand-json' ↓

cause Plugin not installed or not in node_modules, or Prettier cannot locate it.

fix

Run npm install --save-dev prettier-plugin-expand-json and ensure your working directory contains node_modules.

error Error [ERR_REQUIRE_ESM]: require() of ES Module /path/to/prettier-plugin-expand-json/index.js from /path/to/prettier/index.js not supported. ↓

cause Prettier is loading the plugin via require(), but the plugin is ESM-only (since v1). This happens if Prettier version is <3 (which used CJS).

fix

Upgrade Prettier to version 3 or later: npm install --save-dev prettier@3.

error [error] prettier-plugin-expand-json: No parser found for file extension: .json ↓

cause Prettier is not configured to use JSON parser for .json files, or another plugin overrides the parser.

fix

Ensure Prettier config includes "plugins": ["prettier-plugin-expand-json"] and that the plugin is listed last if multiple plugins are used.

Warnings

gotcha Plugin must be listed last in the plugins array when combined with other JSON plugins (e.g., prettier-plugin-sort-json, prettier-plugin-pkg). If not, other plugins may override the formatting. ↓

fix Ensure 'prettier-plugin-expand-json' is the last element in the 'plugins' array in your Prettier config.

breaking Minimum Node engine is >=20. Using older Node versions will cause errors. ↓

fix Upgrade to Node 20 or later.

gotcha Plugin does not provide any options; it forces expansion of all arrays and objects. If you need selective expansion, consider other tools. ↓

fix No workaround; designed to always expand.

Install

npm install prettier-plugin-expand-json

yarn add prettier-plugin-expand-json

pnpm add prettier-plugin-expand-json

Imports

default

wrong

const plugin = require('prettier-plugin-expand-json')

correct

in .prettierrc: { "plugins": ["prettier-plugin-expand-json"] }

Plugin is consumed via Prettier configuration, not imported directly in code.

Quickstart

Install plugin, configure Prettier, and format a JSON file to always expand arrays/objects to multi-line.

npm install --save-dev prettier prettier-plugin-expand-json
echo '{"plugins":["prettier-plugin-expand-json"]}' > .prettierrc
echo '{"a":1,"b":[2,3]}' > test.json
npx prettier --write test.json
cat test.json
# Output:
# {
#   "a": 1,
#   "b": [
#     2,
#     3
#   ]
# }