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ESLint Plugins

important

This page describes how to write your own custom ESLint plugins using typescript-eslint. You should be familiar with ESLint's plugins guide and typescript-eslint Custom Rules before writing custom plugins.

Custom plugins that support TypeScript code and typed linting look very similar to any other ESLint plugin. Follow the same general steps as ESLint's plugins guide > Creating a plugin to set up your plugin. The required differences are noted on this page.

tip

See eslint-plugin-example-typed-linting for an example plugin that supports typed linting.

Package Dependencies​

Your plugin should have the following package.json entries.

For all @typescript-eslint and typescript-eslint packages, keep them at the same semver versions. As an example, you might set each of them to ^8.1.2 or ^7.12.0 || ^8.0.0.

dependencies​

@typescript-eslint/utils is required for the RuleCreator factory to create rules.

devDependencies​

@typescript-eslint/rule-tester is strongly recommended to be able to test rules with our RuleTester.

peerDependencies​

Include the following to enforce the version range allowed without making users' package managers install them:

  • @typescript-eslint/parser and any other parsers users are expected to be using
  • eslint
  • typescript

Those are all packages consumers are expected to be using already.

RuleCreator Usage​

We recommend including at least the following three properties in your plugin's RuleCreator extra rule docs types:

  • description: string: a succinct description of what the rule does
  • recommended?: boolean: whether the rule exists in your plugin's shared "recommended" config
  • requiresTypeChecking?: boolean: whether the rule will use type information, for documentation generators such as eslint-doc-generator

For example, from eslint-plugin-example-typed-linting's utils.ts:

import { ESLintUtils } from '@typescript-eslint/utils';

export interface ExamplePluginDocs {
  description: string;
  recommended?: boolean;
  requiresTypeChecking?: boolean;
}

export const createRule = ESLintUtils.RuleCreator<ExamplePluginDocs>(
  name =>
    `https://github.com/your/eslint-plugin-example/tree/main/docs/${name}.md`,
);

Type Checking and Configs​

Most ESLint plugins export a "recommended" ESLint shared config. Many ESLint users assume enabling a plugin's recommended config is enough to enable all its relevant rules.

However, at the same time, not all users want to or are able to enabled typed linting. If your plugin's rules heavily use type information, it might be difficult to enable those in a recommended config.

You have roughly two options:

  • Have your plugin's recommended config require enabling type information
  • Have a separate config with a name like recommendedTypeChecked

Either way, explicitly mention the strategy taken in your docs.

info

Per Custom Rules > Conditional Type Information, we recommend not changing rule logic based on whether type information is available.

tip

See eslint-plugin-example-typed-linting for an example plugin that supports typed linting.