Highlights

• Report your eslint results as annotations using the GitHub Checks API
• Only runs in CI environment
• Uses eslint-formatter-pretty as the formatter for displaying the lint results

Install

npm install --save-dev eslint-formatter-github
# or
yarn add -D eslint-formatter-github

Usage

You will need to install the github app to your repo.

Then just use the formatter and it will report errors and warnings on PRs!

eslint --format github file.js

Using you own GitHub App (recommended)

You might not want to use our github app for the formatter.

Reasons:

1. You think they way we exposed the keys is bad
2. You are on Github Enterprise and cannot use the public app

In these situations all you need to do is create a GitHub app and set a few environment variables.

1. Create a GitHub app

Go to this page to create a new GitHub app. You need to set the following fields:

• name - The name that shows for your app in the checks reports
• Homepage URL - You can set this to anything. Ours is set to https://github.com
• Webhook URL - You can set this to anything. Ours is set to https://github.com

Then hit Save Changes and you're all done setting up your GitHub app.

You need to configure Permissions for your GitHub app. You need to set the following permissions:

• Checks - Read & Write
• Metadata - Read-only

2. Set ESLINT_APP_ID environment variable

Your GitHub application's ID. This can be found at the top of your GitHub app's edit page.

3. Set ESLINT_PRIVATE_KEY environment variable

The private RSA key for your application. The prompt to generate the RSA key is at the bottom of your GitHub app's edit page.

Once you have generated a key, open the file that is downloaded and copy to text into the PRIVATE_KEY environment variable.

When using GitHub Actions, you can use the environment variable ESLINT_PRIVATE_KEY_BASE64 to set the private key base64 encoded. This fix the issue with the new line characters in the private key.

To encode the private key, you can use the following command:

cat private-key.pem | base64

4. Set GH_API (enterprise only)

To get this package to work on github enterprise instances you will need to set the GH_API environment variable to a url pointing towards your enterprise GitHub's API.

5. (optional) Set GH_CHECK_NAME

If the default check name conflicts with something, you can override it by passing GH_CHECK_NAME environment variable.

Example for GitHub Actions

Warning It is strongly recommended to create your own GitHub app and never share your private key with third parties. Otherwise, unauthorized persons can read meta data and manipulate checks.

name: Lint
on: [pull_request]
jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
        with:
          node-version: 18
      - run: npm install
      - run: eslint src --ext .ts,.js --format github
        env:
          ESLINT_APP_ID: ${{ secrets.ESLINT_APP_ID }}
          ESLINT_PRIVATE_KEY_BASE64: ${{ secrets.ESLINT_PRIVATE_KEY_BASE64 }}