title: React Initial Render Success vs Second Render Failure?
body: <p>I have an inventory component linked to an inventory Firebase. When my component renders for the first time it works perfectly. When I leave the inventory page and come back, however, my component only renders the last item in the inventory database. It is also weird because when I include the <code>console.log('add fired ' + product.data.name);</code> it recognizes every node in the database and logs the product name, but they are still not displayed on the screen. Any help would be greatly appreciated.</p>
  
  <pre class="lang-js prettyprint-override"><code>componentWillMount(){
    //Create reference to inventory db
     this.inventory = firebase.database().ref('inventory');
  
     this.inventory.on('child_added', snapshot =&gt; {
        let product = { data: snapshot.val(), id: snapshot.key };
        console.log('add fired ' + product.data.name);
        this.setState({ products: this.state.products.concat(product) });
    });
  }
  </code></pre>