npm-package-json-lint

What is npm-package-json-lint?

npm-package-json-lint is a tool for linting package.json files, ensuring they adhere to a defined set of rules and best practices. It helps maintain consistency and correctness in package.json files across projects.

What are npm-package-json-lint's main functionalities?

Linting package.json files

This feature allows you to define a set of rules for linting package.json files. The code sample shows a configuration file that extends the default configuration and specifies rules for the name type, version format, and requiring an author field.

module.exports = {
  extends: 'npm-package-json-lint-config-default',
  rules: {
    'name-type': 'error',
    'version-format': 'error',
    'require-author': 'error'
  }
};

Custom rule definitions

You can define custom rules to enforce specific requirements in your package.json files. The code sample demonstrates how to restrict certain dependencies and require the scripts field.

module.exports = {
  rules: {
    'no-restricted-dependencies': ['error', ['lodash', 'underscore']],
    'require-scripts': 'error'
  }
};

Command-line interface

The package provides a CLI for linting package.json files. The code sample shows how to run the linter using npx and a specified configuration file.

npx npm-package-json-lint . --config .npmpackagejsonlintrc.json

Other packages similar to npm-package-json-lint

eslint-plugin-json

eslint-plugin-json is an ESLint plugin that allows you to lint JSON files, including package.json. It provides a way to enforce JSON-specific rules using the familiar ESLint framework. Compared to npm-package-json-lint, it integrates JSON linting into the broader ESLint ecosystem.

jsonlint

jsonlint is a pure JavaScript library for validating and formatting JSON data. While it doesn't provide package.json-specific rules, it ensures that JSON files are syntactically correct. It is more general-purpose compared to npm-package-json-lint.

json-schema

json-schema is a library for validating JSON documents against a JSON Schema. It can be used to enforce a schema for package.json files, ensuring they adhere to a predefined structure. Unlike npm-package-json-lint, it focuses on schema validation rather than linting rules.

README

npm-package-json-lint

A package.json linter for Node projects

What is npm-package-json-lint?

npm-package-json-lint helps enforce standards for your package.json file. Currently it can check for:

• validity of data types in nodes. Ex: name should always be a string.
• whether a string is a lowercase
• whether a version number is a valid
• the presence of a given module
• the presence of a pre-release version of a module
• and much more!

Please see the wiki for a list of rules.

How do I install it?

First thing first, let's make sure you have the necessary pre-requisites.

System Dependencies

Node

• Node.js - v6.0.0+
• npm - v3.0.0+

Use the cli

Use cli globally

• npm install npm-package-json-lint -g

Use cli in project

• npm install npm-package-json-lint

CLI commands and configuration

Command	Alias	Description
npmPkgJsonLint --help	N/A	Lists supported CLI options
npmPkgJsonLint --version	N/A	Lists the current version number
npmPkgJsonLint --configFile	-c	File path to local config file or module name.
npmPkgJsonLint --quiet	-q	Report errors only
npmPkgJsonLint --noConfigFiles	-ncf	Skips loading project config files (i.e. .npmpackagejsonlintrc.json and npmpackagejsonlint.config.js)

Examples

$ npmPkgJsonLint .

Looks for all package.json files in the project. The CLI engine automatically looks for relevant config files for each package.json file that is found.

$ npmPkgJsonLint ./packages

Looks for all package.json files in the packages directory. The CLI engine automatically looks for relevant config files for each package.json file that is found.

$ npmPkgJsonLint ./package1 ./package2

Looks for all package.json files in the package1 and package2 directories. The CLI engine automatically looks for relevant config files for each package.json file that is found.

$ npmPkgJsonLint -c ./config/.npmpackagejsonlintrc.json .

Looks for all package.json files in the project. The CLI engine automatically looks for relevant config files for each package.json file that is found. The CLI also merges the config found in ./config/.npmpackagejsonlintrc.json

$ npmPkgJsonLint --configFile ./config/npmpackagejsonlint.config.json .

Same as above using the long form for specifying config files.

$ npmPkgJsonLint -q .

Looks for all package.json files in the project. The CLI engine automatically looks for relevant config files for each package.json file that is found. Removes any warnings from the output.

$ npmPkgJsonLint --quiet ./packages

Looks for all package.json files in the packages directory. The CLI engine automatically looks for relevant config files for each package.json file that is found. Removes any warnings from the output using the long form for quieting output.

Node.js API

npm-package-json-lint exports two main objects: CLIEngine and NpmPackageJsonLint.

NpmPackageJsonLint()

Creates an instance of NpmPackageJsonLint

NpmPackageJsonLint has one public method, lint. lint takes a package.json object in object form and a config object as parameters.

.lint(packageJsonData, configObj)

Runs configured rules against the provided package.json object.

packageJsonData

Type: object

A package.json file in object form.

configObj

Type: object

A valid configuration object.

Example

The following example demostrates how to use lint.

const NpmPackageJsonLint = require('npm-package-json-lint').NpmPackageJsonLint;

const npmPackageJsonLint = new NpmPackageJsonLint();
const results = npmPackageJsonLint.lint(packageJsonDataAsObject, configObject);

Return

lint returns an object with an array of LintIssues. Please see LintIssue section for more detail.

{
  issues: [
    {
      lintId: 'require-name',
      severity: 'error',
      node: 'name',
      lintMessage: 'name is required'
    }
  ]
}

.version

Calling .version on an instance of NpmPackageJsonLint will return the version number of npm-package-json-lint that the linter is associated with.

Example

const NpmPackageJsonLint = require('npm-package-json-lint').NpmPackageJsonLint;

const npmPackageJsonLint = new NpmPackageJsonLint();

npmPackageJsonLint.version; // => '3.0.0'

CLIEngine(options)

Creates an instance of CLIEngine

options

Type: object

CLIEngine configuration object

• configFile {string} Name of module/file to use.
• cwd {string} The current working diretory for all file operations.
• useConfigFiles {boolean} False disables use of .npmpackagejsonlintrc.json files and npmpackagejsonlint.config.js files.
• rules {object} An object of rules to use.

Example

The following example demostrates how to initialize a CLIEngine.

const CLIEngine = require('npm-package-json-lint').CLIEngine;

const cliEngineOptions = {
  configFile: '',
  cwd: process.cwd(),
  useConfigFiles: true,
  rules: {}
};

const cliEngine = new CLIEngine(cliEngineOptions);

.executeOnPackageJsonFiles(patterns)

Runs npm-package-json-lint against the array a patterns.

patterns

Type: array

An array of glob patterns

Example

The following example demostrates how to use executeOnPackageJsonFiles.

const CLIEngine = require('npm-package-json-lint').CLIEngine;

const cliEngineOptions = {
  configFile: '',
  cwd: process.cwd(),
  useConfigFiles: true,
  rules: {}
};
const patterns = ['.'];

const cliEngine = new CLIEngine(cliEngineOptions);
const results = cliEngine.executeOnPackageJsonFiles(patterns);

Return

executeOnPackageJsonFiles returns an object with an array of results.

{
  results: [
    {
      filePath: './package.json',
      issues: [
        {
          lintId: 'require-name',
          severity: 'error',
          node: 'name',
          lintMessage: 'name is required'
        }
      ],
      errorCount: 1,
      warningCount: 0
    }
  ],
  errorCount: 1,
  warningCount: 0
}

.version

Calling .version on an instance of CLIEngine will return the version number of npm-package-json-lint that the CLIEngine is associated with.

Example

const CLIEngine = require('npm-package-json-lint').CLIEngine;

const cliEngineOptions = {
  configFile: '',
  cwd: process.cwd(),
  useConfigFiles: true,
  rules: {}
};

const cliEngine = new CLIEngine(cliEngineOptions);

cliEngine.version; // => '3.0.0'

WARNING

Only the functions documented above are supported. All other functions that are exposed may change with any release. Please refrain from using them.

Lint Rules

npm-package-json-lint has a configurable set of rules. Please see the wiki for a full list of available rules. By default no rules are enabled. If you would like to use npm-package-json-lint's default ruleset, please see npm-package-json-lint-config-default.

Each rule contains the following properties:

1. ID - example: require-author
2. Node - example: author
3. Message - example: author is required
4. Rule Type - example: required

As of v2.7.0, there are multiple ways to provide a configuration object.

1. Adding a --configFile to the command to specify a JSON file. This file is named .npmpackagejsonlintrc.json.
2. Add a npmPackageJsonLintConfig property in package.json file
3. Add a npmpackagejsonlint.config.js file that exports a config object in the current working directory.
4. Add a global .npmpackagejsonlintrc.json file in the root of your user directory
5. Add a global npmpackagejsonlint.config.js file that exports a config object in the root of your user directory

Configuring rules

npm-package-json-lint rules can either be run as an error, warning, or off.

• "warning" - run the rule as a warning
• "error" - run the rule as an error
• "off" - disables the rule

Ex: "require-author": "error"

Migrating from v2.x.x to 3.x.x

Please see the migration guide.

Migrating from v1.x.x to 2.x.x

Please see the migration guide.

Migrating from v0.x.x to 1.x.x

Please see the migration guide.

Contributing

Please see CONTRIBUTING.md.

Release History

Please see CHANGELOG.md.

Related

• grunt-npm-package-json-lint: Grunt Wrapper for npm-package-json-lint
• npm-package-json-lint-config-default: Shared default configuration module for npm-package-json-lint

License

Copyright (c) 2016-2018 Thomas Lindner. Licensed under the MIT license.