eslint-plugin-json

4.0.1 verified Sat Apr 25 auth: no javascript

ESLint plugin for linting JSON files. Version 4.0.1 supports ESLint flat config and requires Node >=18. It uses VSCode's JSON parser for linting, replacing JSHint in v1.3.1. Recommended for ensuring valid JSON, catching duplicate keys, trailing commas, and other issues. Supports allowing comments. The plugin ships with recommended configs for both flat and legacy ESLint formats.

Common errors

error Failed to load plugin 'json': Cannot find module 'eslint-plugin-json' ↓

cause Plugin not installed or not in node_modules.

fix

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

error ESLint: Error while loading rule 'json/undefined': Rule not found ↓

cause Legacy config using individual rules without specifying processor.

fix

Add processor: 'json/json' in flat config or use recommended config.

error ESLint: Expected linebreaks to be 'LF' but found 'CRLF' ↓

cause This rule is from another plugin (e.g., eslint-plugin-linebreak), not this one.

fix

This is not a json plugin issue; configure linebreak-style rule elsewhere.

Warnings

breaking ESLint v9+ requires flat config; plugin v4+ needed. ↓

fix Use eslint-plugin-json v4+ and flat config format (eslint.config.js).

breaking ESLint v9 dropped --ext flag support for some formats; use files in flat config. ↓

fix Define files glob in eslint.config.js instead of --ext .json.

gotcha The rule json/* applies all linting rules; configuring individual rules may override. ↓

fix Use individual rules like 'json/undefined' for granular control, or set severity on json/*.

gotcha Legacy configs (recommended-legacy) are deprecated in favor of flat config. ↓

fix Migrate to flat config and use recommended config.

deprecated Use of .eslintrc config format is deprecated for new projects with ESLint v9+. ↓

fix Switch to eslint.config.js (flat config).

Install

npm install eslint-plugin-json

yarn add eslint-plugin-json

pnpm add eslint-plugin-json

Imports

default
```
import json from 'eslint-plugin-json'
```
ESM import for flat config (ESLint v9+). Also works with require in legacy.
json
```
import json from 'eslint-plugin-json'
```
Import the plugin object for flat config.
configs (recommended)
```
json.configs['recommended']
```
Access recommended config for flat config.
configs (recommended-legacy)
```
json.configs['recommended-legacy']
```
Access legacy recommended config for .eslintrc.

Quickstart

Basic flat config setup to lint all .json files using the recommended config.

// eslint.config.js (flat config)
import json from 'eslint-plugin-json';

export default [
  {
    files: ['**/*.json'],
    ...json.configs['recommended']
  }
];
// Then run: npx eslint . --ext .json