eslint-config-liferay v21.1.0

eslint-config-liferay

An ESLint shareable config that helps enforce the Liferay Frontend Guidelines.

Overview

Installation

$ npm install --save-dev eslint eslint-config-liferay

Usage

Once the eslint-config-liferay package is installed, you can use it by specifying liferay in the extends section of your ESLint configuration.

module.exports = {
	extends: ['liferay'],
};

This preset provides a reasonable starting point for an independent open source project.

liferay-portal

In liferay-portal itself we extend the liferay/portal preset instead, which activates some rules specific to liferay-portal. This preset assumes the use of React, and also provides a set of custom rules that are described in detail in the eslint-plugin-liferay-portal section below.

This extension is applied automatically by liferay-npm-scripts, so you don't have to configure it explicitly.

An important disclaimer about the use of ESLint in liferay-portal

JavaScript code that appears inline inside JSP files and other templates is only lightly checked by ESLint, because JSP is an impoverished environment where we have to work with context-free snippets of text as opposed to fully-formed, valid JS modules. Our long-term strategy is to move as much code as possible out of JSP and into React components, but in the interim, please be aware that the level of safety provided by the linter inside JSP is greatly reduced.

React

For React projects outside of liferay-portal, you can extend liferay/react instead:

module.exports = {
	extends: ['liferay/react'],
};

metal-jsx

For legacy projects inside liferay-portal that use metal-jsx, we have a "metal" preset:

module.exports = {
	extends: ['liferay/metal'],
};

Use this preset to stop ESLint from spuriously warning that variables that are used as JSX components are unused.

Copyright headers

The included eslint-plugin-notice plug-in can be used to enforce the use of uniform copyright headers across a project by placing a template named copyright.js in the project root (for example, see the file defining the headers used in eslint-config-liferay itself) and configuring the rule:

const path = require('path');

module.exports = {
	extends: ['liferay'],
	rules: {
		'notice/notice': [
			'error',
			{
				templateFile: path.join(__dirname, 'copyright.js'),
			},
		],
	},
};

Explicit configuration is required in order to make overrides possible; for example:

• top-level/
  • .eslintrc.js
  • copyright.js
  • mid-level/
    • .eslintrc.js
    • copyright.js
    • bottom-level/
      • .eslintrc.js

If we were to provide configuration by default, then if bottom-level/.eslintrc.js does an extends: ['liferay'], then the default configuration would be considered more local than the one provided by mid-level, causing the wrong copyright.js to be used.

Base rules

Custom rules

eslint-plugin-liferay

The bundled eslint-plugin-liferay plugin includes the following rules:

• liferay/array-is-array: Enforces (and autofixes) the use of Array.isArray() over instanceof Array.
• liferay/destructure-requires: Enforces (and autofixes) that require statements use destructuring.
• liferay/group-imports: Enforces (and autofixes) import and require grouping.
• liferay/import-extensions: Enforces consistent usage/omission of file extensions in imports.
• liferay/imports-first: Enforces that imports come first in the file.
• liferay/no-absolute-import: Enforces that imports do not use absolute paths.
• liferay/no-arrow: Bans arrow functions (for IE; not on by default).
• liferay/no-duplicate-class-names: Enforces (and autofixes) uniqueness of class names inside JSX className attributes.
• liferay/no-duplicate-imports: Enforces at most one import of any given module per file.
• liferay/no-dynamic-require: Enforces that require() calls use static arguments.
• liferay/no-it-should: Enforces that it() descriptions start with a verb, not with "should".
• liferay/no-require-and-call: Enforces that the result of a require() call at the top level is not immediately called.
• liferay/padded-test-blocks: Enforces blank lines between test blocks (it() etc).
• liferay/sort-class-names: Enforces (and autofixes) ordering of class names inside JSX className attributes.
• liferay/sort-imports: Enforces (and autofixes) import and require ordering.
• liferay/sort-import-destructures: Enforces (and autofixes) ordering of destructured names in import statements.
• liferay/trim-class-names: Enforces (and autofixes) that class names inside JSX className attributes do not have leading or trailing whitespace.

eslint-plugin-liferay-portal

The bundled eslint-plugin-liferay-portal plugin includes the following rules:

• liferay-portal/deprecation: Enforces standard formatting of @deprecated annotations.
• liferay-portal/no-global-fetch: Prevents usage of unwrapped fetch to avoid possible issues related to security misconfiguration.
• liferay-portal/no-explicit-extend: Prevents unnecessary extensions in ESLint and Babel configuration files.
• liferay-portal/no-loader-import-specifier: Ensures that ".scss" files imported via the loader are used only for side-effects.
• liferay-portal/no-metal-plugins: Prevents usage of deprecated metal-* plugins and utilities.
• liferay-portal/no-react-dom-render: Prevents direct usage of ReactDOM.render in favor of our wrapper.
• liferay-portal/no-side-navigation: Guards against the use of the legacy jQuery sideNavigation plugin.

License

MIT