code: function getPort(config, skyPagesConfig) {
    return new Promise((resolve, reject) => {
      const configPort = skyPagesConfig &&
        skyPagesConfig.skyux &&
        skyPagesConfig.skyux.app &&
        skyPagesConfig.skyux.app.port;
  
      if (configPort) {
        resolve(configPort);
      } else if (config.devServer && config.devServer.port) {
        resolve(config.devServer.port);
      } else {
        portfinder.getPortPromise()
          .then(port => resolve(port))
          .catch(err => reject(err));
      }
    });
  }
docs: Let users configure port via skyuxconfig.json first.
  Else another plugin has specified devServer.port, use it.
  Else, find us an available port.
  @name getPort
  @returns {Number} port