title: Show all Items of a AngularFire2 List
body: <p>how to reset a filter or initially show all records, please ?</p>
  
  <p>reference:
  <a href="https://github.com/angular/angularfire2/blob/master/docs/4-querying-lists.md#creating-a-query-with-observable-values" rel="nofollow">https://github.com/angular/angularfire2/blob/master/docs/4-querying-lists.md#creating-a-query-with-observable-values</a></p>
  
  <p>Example app:</p>
  
  <pre><code>import { Component } from '@angular/core';
  import { AngularFire, FirebaseListObservable,     FirebaseObjectObservable } from 'angularfire2';
  import { Subject } from 'rxjs/Subject';
  
  @Component({
    selector: 'app-root',
    template: `
    &lt;ul&gt;
      &lt;li *ngFor="let item of items | async"&gt;
        {{ item.text }}
      &lt;/li&gt;
    &lt;/ul&gt;
    &lt;div&gt;
      &lt;h4&gt;Filter by size&lt;/h4&gt;
      &lt;button (click)="filterBy('small')"&gt;Small&lt;/button&gt;
      &lt;button (click)="filterBy('medium')"&gt;Medium&lt;/button&gt;
      &lt;button (click)="filterBy('large')"&gt;Large&lt;/button&gt;
    &lt;/div&gt;
    `,
  })
  export class AppComponent {
    items: FirebaseListObservable&lt;any[]&gt;;
    sizeSubject: Subject&lt;any&gt;;
  
    constructor(af: AngularFire) {
      this.sizeSubject = new Subject();
  
      //////////////////////////////////////////
      SHOW ALL RECORDS instead of none (at this state nothing is shown util the sizeSubject.next is set) 
      //////////////////////////////////////////
      this.items = af.database.list('/items', {
        query: {
          orderByChild: 'size',
          equalTo: this.sizeSubject
        }
      });
  
    }
    filterBy(size: string) {
      this.sizeSubject.next(size); 
    }
  }
  </code></pre>