ESLint JSON Language Plugin

Overview

This package contains a plugin that allows you to natively lint JSON and JSONC files using ESLint.

Important: This plugin requires ESLint v9.6.0 or higher and you must be using the new configuration system.

Installation

For Node.js and compatible runtimes:

npm install @eslint/json -D
# or
yarn add @eslint/json -D
# or
pnpm install @eslint/json -D
# or
bun install @eslint/json -D

For Deno:

deno add @eslint/json

Usage

This package exports these languages:

• "json/json" is for regular JSON files
• "json/jsonc" is for JSON files that support comments (JSONC) such as those used for Visual Studio Code configuration files
• "json/json5" is for JSON5 files

Depending on which types of JSON files you'd like to lint, you can set up your eslint.config.js file to include just the files you'd like. Here's an example that lints JSON, JSONC, and JSON5 files:

import json from "@eslint/json";

export default [
	{
		plugins: {
			json,
		},
	},

	// lint JSON files
	{
		files: ["**/*.json"],
		language: "json/json",
		rules: {
			"json/no-duplicate-keys": "error",
		},
	},

	// lint JSONC files
	{
		files: ["**/*.jsonc", ".vscode/*.json"],
		language: "json/jsonc",
		rules: {
			"json/no-duplicate-keys": "error",
		},
	},

	// lint JSON5 files
	{
		files: ["**/*.json5"],
		language: "json/json5",
		rules: {
			"json/no-duplicate-keys": "error",
		},
	},
];

Recommended Configuration

To use the recommended configuration for this plugin, specify your matching files and then use the json.configs.recommended object, like this:

import json from "@eslint/json";

export default [
	// lint JSON files
	{
		files: ["**/*.json"],
		ignores: ["package-lock.json"],
		language: "json/json",
		...json.configs.recommended,
	},

	// lint JSONC files
	{
		files: ["**/*.jsonc"],
		language: "json/jsonc",
		...json.configs.recommended,
	},

	// lint JSON5 files
	{
		files: ["**/*.json5"],
		language: "json/json5",
		...json.configs.recommended,
	},
];

Note: You generally want to ignore package-lock.json because it is auto-generated and you typically will not want to manually make changes to it.

Rules

• no-duplicate-keys - warns when there are two keys in an object with the same text.
• no-empty-keys - warns when there is a key in an object that is an empty string or contains only whitespace (note: package-lock.json uses empty keys intentionally)

License

Apache 2.0