//emit next and error notifications

const source = Rx.Observable

  .from([

    Rx.Notification.createNext('SUCCESS!'),

    Rx.Notification.createError('ERROR!')   

  ])

  //turn notification objects into notification values

  .dematerialize();

​

//output: 'NEXT VALUE: SUCCESS' 'ERROR VALUE: 'ERROR!'

const subscription = source.subscribe({

  next: val => console.log(`NEXT VALUE: ${val}`),

  error: val => console.log(`ERROR VALUE: ${val}`)

});