Map Rxjs Angular 8

Map operator in rxjs is the same as the map of an array the only defense is map operator will work with observable and returns the manipulated value as the v. This below code works fine: Map operator applies a given function to each value emitted by source observable and any resulting values as an observable.

1 2 3 4 5 6 7 multiplyby2() { this.srcarray.pipe(map(val = > { return val * 2})) Map to inner observable, ignore other values until that observable completes. Property 'map' does not exist on type 'observable'.

This.questions$ = dbquestions$.map (snapshots => snapshots.map (data => this.filtercontrols (data) ));

I am using angularfire with rxjs 5.4.0 and firebase. In this video you learned some basics about rxjs and streams in angular. Map() transforms each value of the source observable using the passed formula. This below code works fine: