visgl / loaders.gl / 24139120841

// Copyright (c) vis.gl contributors

import ChildProcess from 'child_process';

// Get an available port

// Works on Unix systems

export function getAvailablePort(defaultPort: number = 3000): Promise<number> {

  return new Promise(resolve => {

    // Get a list of all ports in use

    ChildProcess.exec('lsof -i -P -n | grep LISTEN', (error, stdout) => {

      if (error) {

        // likely no permission, e.g. CI

        resolve(defaultPort);

        return;

      }

      const portsInUse: number[] = [];

      const regex = /:(\d+) \(LISTEN\)/;

      stdout.split('\n').forEach(line => {

        const match = regex.exec(line);

        if (match) {

          portsInUse.push(Number(match[1]));

        }

      });

      let port = defaultPort;

      while (portsInUse.includes(port)) {

        port++;

      }

      resolve(port);

    });

  });

}