'use strict'; const net = require('net'); const options = { port: 0, reusePort: true }; function checkSupportReusePort() { return new Promise((resolve, reject) => { const server = net.createServer().listen(options); server.on('listening', () => { server.close(resolve); }); server.on('error', (err) => { console.log('The `reusePort` option is not supported:', err.message); server.close(); reject(err); }); }); } module.exports = { checkSupportReusePort, options, };