Jenkins step to run Yarn Audit exiting only on critical level vulnerabilities

Jenkinsfile

// Run yarn audit and only exit 0 on critical vulnerabilities (greater than 8)
// https://github.com/yarnpkg/yarn/blob/298e0ea6cea3ab8a610cabf28de3fdf8e7fa8d1f/src/cli/commands/audit.js#L158-L162
//
// Credit: https://github.com/yarnpkg/yarn/issues/7260#issuecomment-506556626

stage('Node dependencies') {
  steps {
    sh script: '/bin/bash -c "yarn audit; [[ $? -ge 8 ]] && exit 1 || exit 0"', label: "Vulnerability audit"
    sh script: 'yarn', label: 'Install dependencies'
  }
}