如何在AngularFire2 / FireStore中查询子集合？

Question

I am trying to query subcollections in AngularFire2 with FireStore with no success. Have searched but found no suitable solution.

ngOnInit() {
// this does work
this.africaCollection = this.afs.collection('Country', ref => ref
.where('code', '==', 'za'));
this.countriesAfrica = this.africaCollection.valueChanges();

// this does not work
this.townCollection = this.afs.collection('Country').doc('za')                         
.collection('Towns');
this.towns = this.townCollection.valueChanges();
{

My HTML looks like this:

<div>
  <table>
    <tr *ngFor="let town of towns | async">
      <td>{{ town.name }}</td>
    </tr>
  </table>
</div>

I am a newbie at this.

Answer 1

It may be related to your rules.

Default rules

service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write;
    }
  }
}

More details about rules here:

https://firebase.google.com/docs/firestore/security/secure-data#rules_dont_cascade

Make sure you have items in that collection

You can also add items to your collection by code to be sure it's correctly located. You'll then be able to look at your firebase console to see where it's been placed.

var town: Town = {
  name: "town name",
  region: "region name"
};
this.afs.collection('Country').doc('za').collection('Towns').add(town);