https://github.com/origin-1/eslint-p
A drop-in replacement for ESLint 9 featuring multithreaded parallel linting.
https://github.com/origin-1/eslint-p
concurrency eslint multithreading parallel
Last synced: 2 months ago
JSON representation
A drop-in replacement for ESLint 9 featuring multithreaded parallel linting.
- Host: GitHub
- URL: https://github.com/origin-1/eslint-p
- Owner: origin-1
- License: other
- Created: 2023-12-01T14:59:12.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2025-04-22T14:23:39.000Z (3 months ago)
- Last Synced: 2025-04-30T15:48:22.938Z (2 months ago)
- Topics: concurrency, eslint, multithreading, parallel
- Language: JavaScript
- Homepage:
- Size: 380 KB
- Stars: 28
- Watchers: 1
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# eslint-p · [![npm version][npm badge]][npm URL]
A drop-in replacement for ESLint 9 featuring multithreaded parallel linting.
> **IMPORTANT:** Legacy `.eslintrc` configuration is not supported.
## Installation
```shell
npm i --save-dev eslint-p
```
```shell
yarn add --dev eslint-p
```
```shell
pnpm add --save-dev eslint-p
```
## Usage
All [ESLint CLI options](https://eslint.org/docs/latest/use/command-line-interface#options) are supported, plus `--concurrency` to specify the number of linting threads explicitly.
Example:
```shell
npx eslint-p --fix --concurrency=4
```
Valid values for the `--concurrency` option are:
* **positive integers (e.g. `4`)**:
Maximum number of linting threads. The effective number of threads can be lower when linting only a few files.
* **`auto`**:
Choose number of linting threads automatically (default).
* **`off`**:
No multithreading, run like ESLint. This is not the same as `--concurrency=1`.
> **NOTE**: Normally, a performance improvement **will be only noticeable on systems with 4 or more CPUs**.
> Some plugins like `typescript-eslint` with type-aware linting can increase the time required to initialize a linting thread resulting in performance degradation when multithreading is used.
## Mixed Usage with ESLint
This package has ESLint set as a dependency, so if you already have `eslint` installed, but with a different version than the one specified in the `package.json` of this package you might get inconsistent results between the CLI and the editor.
To check the version of ESLint used by this package you can use:
```shell
npx eslint-p -v
```
To avoid inconsistencies, install the same `eslint` version used by this package or remove the `eslint` dependency from your `package.json`.
You can find more information on [this pull request](https://github.com/origin-1/eslint-p/pull/1).
## Concurrency Debugging
When the `--debug` option is passed and the command runs in multithread mode, the debug output will include a line indicating the number of worker threads in use. For example:
```shell
npx eslint-p --debug
```
will print a line similar to:
```text
eslint:eslint Running 4 worker thread(s). +0ms
```
This line should be printed in the first seconds of execution, before any files are processed, but it can be easily overlooked.
To make the debug output less verbose in a Unix shell you can run instead:
```shell
DEBUG='eslint:eslint' npx eslint-p
```
Or in Windows PowerShell:
```shell
$env:DEBUG='eslint:eslint' ; npx eslint-p
```
If you don't see a lint containing `worker thread(s)` in the debug output, then the command is running in single-threaded mode, i.e. like ESLint itself.
## Multithread Linting in ESLint
ESLint is considering the possibility of integrating multithread linting as a built-in feature.
You can follow [the related proposal](https://github.com/eslint/rfcs/pull/129) for more information.
[npm badge]: https://img.shields.io/npm/v/eslint-p?logo=npm
[npm URL]: https://www.npmjs.com/package/eslint-p