nl_tokens: / * Check if the port is already in use
pl_tokens: function isPortTaken ( port : number ) : Promise < boolean > { return <mask> Promise ( resolve => { const portTester = net . createServer ( ) . once ( 'error' , ( ) => { return resolve ( true ) ; } ) . once ( 'listening' , ( ) => { portTester . close ( ) ; resolve ( false ) ; } ) . listen ( port ) ; } ) ; }