import {Injectable} from '@angular/core';import {Skill} from '../models/skills';import {AuthService} from '../../auth/services/auth.service';import 'rxjs/add/operator/do';import 'rxjs/add/operator/startWith';import 'rxjs/add/operator/catch';import {Observable} from 'rxjs/Observable';import {AngularFirestore, AngularFirestoreCollection} from 'angularfire2/firestore';@Injectable()export class SkillsService {  skillCollection: AngularFirestoreCollection
     
      ;  skills: Observable
      
       ;  events: Observable
       
        ;  constructor(private afs: AngularFirestore,              private authService: AuthService) {    this.skillCollection = afs.collection(`users/${this.uid}/skills`,      ref => ref.orderBy('name').limit(10));    this.events = this.skillCollection.auditTrail();  }  get uid() {    return this.authService.user.uid;  }  getSkills(): Observable
        
          {    return this.skillCollection      .snapshotChanges()      .startWith([]) // To solve the snapshotChange doesn't fire for empty data      .map((actions) =>        actions.map(({payload}) => ({id: payload.doc.id, ...payload.doc.data()} as Skill))      );  }  getSkill(key): Observable
         
           {    return this.afs.doc(`users/${this.uid}/skills/${key}`)      .snapshotChanges()      .map(({payload}) => ({id: payload.id, ...payload.data()} as Skill));  }  addSkill(skill: Skill) {    return this.skillCollection.add(skill);  }  updateSkill(key: string, skill: Partial
          
           ) { return this.afs.doc
           
            (`users/${this.uid}/skills/${key}`).update(skill); } removeSkill(key: string) { return this.afs.doc
            
             (`users/${this.uid}/skills/${key}`).delete(); }}