angular - AngularFire .subscribe => console.log returning undefined after use of map or flatMap -

i'm pretty new angularfire, firebase, rxjs etc..

can tell me why following returns 'undefined' console.log?

    this.af.database.object('/teams/' + this.id)         .map((data) => {             data.teamname = teams[data.team];         })         .subscribe((data) => {             console.log(data)         }) 

teams enum. red = 1, blue = 2...

i know problem lies in .map if remove , log x or log enum lookup both work fine..

this works fine (and resolves red):

    this.af.database.object('/teams/' + this.id)         .subscribe((x) => {             console.log(teams[x.team]);         }) 

as (resolving firebase observable):

    this.af.database.object('/teams/' + this.id)         .subscribe((x) => {             console.log(x);         }) 

i've tried flatmap on list rather map on object.

any appreciated.

because returns both get , map methods observable, not json.

in

 .map((data) => {             data.teamname = teams[data.team];         }) 

you treat data variable json isn't. variable becomes undefined. because there's no such thing data.teamname

ref: https://angular.io/docs/ts/latest/guide/server-communication.html#!#fetch-data

http.get method returns observable of http responses (observable) rxjs library , map 1 of rxjs operators.