Associate Firebase users with database items based on their UID

database.rules.json

  "rules": {
    "items": {
       "$uid": {
         ".read": "$uid === auth.uid",
         ".write": "$uid === auth.uid"
       }
     }
   }

items.service.ts

/// Data Structure in Firebase

// -|items
//     -|userID
//         -|itemId


import { Injectable } from '@angular/core';
import { AngularFireDatabase, FirebaseListObservable, FirebaseObjectObservable } from 'angularfire2/database';
import { Item } from './item';
import { AngularFireAuth } from 'angularfire2/auth';

@Injectable()
export class ItemService {

  items: FirebaseListObservable<Item[]> = null; //  list of objects
  userId: string;

  constructor(private db: AngularFireDatabase, private afAuth: AngularFireAuth) {
    this.afAuth.authState.subscribe(user => {
      if(user) this.userId = user.uid
    })
  }


  // Return an observable list with optional query
  // You will usually call this from OnInit in a component
  getItemsList(query={}): FirebaseListObservable<Item[]> {
    if (!this.userId) return;
    this.items = this.db.list(`items/${this.userId}`, {
      query: query
    });
    return this.items
  }


  // Create a bramd new item
  createItem(item: Item): void  {
    this.items.push(item)
      .catch(error => this.handleError(error))
  }


  // Update an exisiting item
  updateItem(key: string, value: any): void {
    this.items.update(key, value)
      .catch(error => this.handleError(error))
  }

  // Deletes a single item
  deleteItem(key: string): void {
      this.items.remove(key)
        .catch(error => this.handleError(error))
  }

  // Deletes the entire list of items
  deleteAll(): void {
      this.items.remove()
        .catch(error => this.handleError(error))
  }


  // Default error handling for all actions
  private handleError(error) {
    console.log(error)
  }


}