check-port.ts

/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import { Observable } from 'rxjs';
const portfinder = require('portfinder');


export function checkPort(port: number, host: string, basePort = 49152): Observable<number> {
  return new Observable(obs => {
    portfinder.basePort = basePort;
    // tslint:disable:no-any
    portfinder.getPort({ port, host }, (err: any, foundPort: number) => {
      if (err) {
        obs.error(err);
      } else if (port !== foundPort && port !== 0) {
        // If the port isn't available and we weren't looking for any port, throw error.
        obs.error(`Port ${port} is already in use. Use '--port' to specify a different port.`);
      } else {
        // Otherwise, our found port is good.
        obs.next(foundPort);
        obs.complete();
      }
    });
  });
}