Custom formatters/reporters for GitHub Actions

github-action-eslint-formatter.js

const { issueCommand, issue } = require('@actions/core/lib/command')

const pathPrefixLength = process.cwd().length + 1

module.exports = results => {
  issue('group', 'ESLint Annotations')

  for (const result of results) {
    for (const message of result.messages) {
      const { fatal, severity, line, column: col } = message

      const status = fatal || severity === 2 ? 'error' : 'warning'
      const file = result.filePath.substr(pathPrefixLength)
      const data = { file, line, col }
      const description = `${message.message} (${message.ruleId})`

      issueCommand(status, data, description)
    }
  }

  issue('endgroup')

  return ''
}

github-action-mocha-reporter.js

const { issueCommand, issue } = require('@actions/core/lib/command')
const Mocha = require('mocha')

const pathPrefixLength = process.cwd().length + 1

const stackRe = /^\s*at Context.* \(([^()]+):([0-9]+):([0-9]+)\)/gm

module.exports = class GitHubActionsReporter {
  constructor(runner) {
    runner
      .once('start', () => {
        issue('group', 'Mocha Annotations')
      })
      .on('fail', (test, err) => {
        const [, _file, line, col] = stackRe.exec(err.stack) || []

        const file = _file || test.file.substr(pathPrefixLength)
        const data = { file, line, col }
        const description = `${err.message} (${test.fullTitle()})`

        issueCommand('error', data, description)
      })
      .once('end', () => {
        issue('endgroup')
      })
  }
}