vite-plugin-port-scanner.ts

import portscanner from 'portscanner';
import { PluginOption } from 'vite';

export default function vitePortScanner() {
  return {
    name: 'vite-port-scanner-plugin', // Name of your plugin (required)

    // Vite config hooks
    async config(config, { command }) {
      if (command === 'serve') {
        const startPort = config.server?.port || 5173;
        const port = await portscanner.findAPortNotInUse(
          startPort,
          startPort + 100
        );
        if (port !== startPort) {
          // eslint-disable-next-line no-console
          console.warn(
            `  Port ${startPort} is busy. Using port ${port} instead.`
          );
          config.server = { ...(config.server || {}), port };
        }
      }
    }
  } as PluginOption;
}