title: Firebase equalTo not working
body: <p>My data in firebase looks as shown below. </p>
  
  <pre><code>items {
     item1: {
        field1: value1
        field2: value2
     }
     item2: {
        field1: value4
        field2: value3
     }
  }
  </code></pre>
  
  <p>Now, I want to get all items where field2===value3. When I run the following query, I'm getting all items. Why?</p>
  
  <pre><code>firebase.database().ref().child('items')
          .orderByChild('field2')
          .equalTo('value3')
          .limitToLast(10)
          .once('value');
  </code></pre>