title: Access Firebase node without knowing the previous one
body: <p>I'm making an app with Ionic and Firebase where I create some nodes (inside others) using <code>push()</code> and the problem is that I want to be able to delete that with the app, but as I'm using <code>push()</code> I don't know the push key that it creates.</p>
  
  <p>Firebase Database</p>
  
  <p><a href="https://i.stack.imgur.com/LrsKJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LrsKJ.png" alt="enter image description here"></a></p>
  
  <p>practica.service.ts: Service where I delete the object with push key= -LE8mCntS-7c-aXMgpEa</p>
  
  <pre><code>public eliminarGrupo(grupo){
      this.afDB.database.ref('practicas/' + practica.id + '/grupos/').remove(practica.grupo);
  }
  </code></pre>
  
  <p>grupo-detalle.ts: Typescript code from where I call to the service</p>
  
  <pre><code>eliminarGrupo(){
      this.practicaService.eliminarGrupo(this.grupo);
  }
  </code></pre>
  
  <p>I didn't put the Typescript code where I get the object 'grupo' and those things because that works and it is not really necessary.
  What I want to do is to delete the object 'grupo' but as I don't know the push key I don't know how to access to that object.</p>
  
  <p>I hope you understood my problem, if not, ask whatever you need. I really need your help :'(</p>