@Pipe({

​

  name: 'demopipe',

​

  pure : true/false 

​

})

​

export class DemopipePipe implements PipeTransform {

myObservable.subscribe(

  x => console.log('Observer got a next value: ' + x),

  err => console.error('Observer got an error: ' + err),

  () => console.log('Observer got a complete notification')

);