inside-ci/index.js

#!/usr/bin/env node

module.exports.insideCi = function insideCi() {
  // Bail out if this is specifically overwritten to false.
  if (process.env.CI === 'false') return false

  return !!['CI','CI_APP_ID','BUILD_NUMBER','CI_NAME','RUN_ID'].some(x => process.env[x])
}

if (require.main === module) {
  process.exit(insideCi() ? 0 : 1)
}