eslint-plugin-json-format

2.0.1 verified Fri May 01 auth: no javascript maintenance

An ESLint plugin to lint, format, auto-fix, and sort JSON files. Version 2.0.1 is the latest stable release (last updated September 2019). It extends ESLint's capabilities to handle .json and rc files (like .eslintrc, .babelrc) with auto-fix support. Key differentiators include built-in package.json sorting (standard/pro/custom order), ignoring JSON-with-comments files like tsconfig.json, and ignoring package-lock.json by default. Requires ESLint >= 3.2.1. The plugin is in maintenance mode with no recent updates.

Common errors

error Cannot read property 'getFilename' of undefined ↓

cause ESLint version mismatch: plugin requires ESLint >= 3.2.1, but used with an older version.

fix

Update ESLint to version >=3.2.1: npm install eslint@latest --save-dev

error Configuration for rule "json-format/json-format" is invalid ↓

cause Trying to configure a rule that does not exist or using incorrect rule name prefix.

fix

Use 'json-format/sort-package-json' or 'json-format/*' wildcard, not 'json-format/json-format'. Example: 'rules': { 'json-format/*': 'error' }

error ESLint couldn't find the plugin "eslint-plugin-json-format" ↓

cause Plugin not installed or not listed in package.json dependencies.

fix

Run 'npm install eslint-plugin-json-format --save-dev' and ensure your ESLint config file is in the project root.

error Unexpected token / in JSON at position 0 ↓

cause Plugin tried to parse a JSON file with comments (JSONC) without explicit configuration.

fix

Add the file pattern to 'json/json-with-comments-files' setting or remove comments from the file.

Warnings

breaking In v2.0.0, the setting 'package-json-sort-order' was renamed to 'sort-package-json'. ↓

fix Use 'json/sort-package-json' instead of 'json/package-json-sort-order'.

breaking The 'sort-package-json' setting now expects a string ('standard', 'pro', false) or an array. Previously it accepted a different format. ↓

fix Update your configuration to match the new schema (e.g., 'json/sort-package-json': 'standard').

gotcha The plugin will strip comments from files listed in 'json-with-comments-files' (like tsconfig.json) if linted with --fix. ↓

fix Do not include files that require comments (e.g., .vscode/settings.json) in 'json-with-comments-files', or disable auto-fix for those files.

gotcha To lint hidden files (e.g., .eslintrc.json), you must explicitly include them using a .eslintignore or the --ext flag with explicit names. ↓

fix Add '!.*' to .eslintignore or use 'eslint --ext .js,.json input/.eslintrc.json'.

deprecated The plugin is no longer actively maintained; last release was in 2019. ↓

fix Consider alternatives like eslint-plugin-json or eslin-plugin-jsonc for newer ESLint versions.

Install

npm install eslint-plugin-json-format

yarn add eslint-plugin-json-format

pnpm add eslint-plugin-json-format

Imports

plugin
wrong
```
plugins: ['eslint-plugin-json-format']
```
correct
```
plugins: ['json-format']
```
ESLint automatically prefixes 'eslint-plugin-', so use 'json-format' in plugins array.
settings
wrong
```
settings: { json/sort-package-json: 'standard' }
```
correct
```
settings: { 'json/sort-package-json': 'standard' }
```
The setting key must be quoted because it contains a slash. Also, 'sort-package-json' was renamed from 'package-json-sort-order' in v2.0.0.
rules
wrong
```
rules: { 'json/*': 'error' }
```
correct
```
rules: { 'json-format/*': 'error' }
```
Rule names are prefixed with 'json-format/' (e.g., 'json-format/sort-package-json', 'json-format/json-format').

Quickstart

Install ESLint and the plugin, create a minimal .eslintrc.json configuration, and run ESLint with --fix on JSON files to auto-format and sort.

npm install eslint --save-dev
npm install eslint-plugin-json-format --save-dev

echo '{"plugins":["json-format"],"settings":{"json/sort-package-json":"standard","json/ignore-files":["**/package-lock.json"],"json/json-with-comments-files":["**/tsconfig.json",".vscode/**"]}}' > .eslintrc.json

echo '{"name":"test","version":"1.0.0","scripts":{"test":"echo \"Error: no test specified\" && exit 1"},"license":"ISC"}' > package.json

eslint --ext .js,.json,.eslintrc,.babelrc --fix .