Could not find iPhone X simulator. Run CLI with --verbose flag for more details

I downloaded the recently released Xcode 11 beta version, and now I can't run my React-Native app on my simulator. I know there are some question on stack-overflow about this but they did'nt help. the problem is there is no

/node_modules/react-native/local-cli/runIOS/findMatchingSimulator.js

file at all. in the local-cli folder there is only one file named cli.js

'use strict';

var cli = require('@react-native-community/cli');

if (require.main === module) {
  cli.run();
}

module.exports = cli;