@loaders.gl/worker-utils/dist/lib/process-utils/process-utils.js

Utilities for running tasks on worker threads

// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
import ChildProcess from 'child_process';
// Get an available port
// Works on Unix systems
export function getAvailablePort(defaultPort = 3000) {
    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 = [];
            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);
        });
    });
}