title: Can't use Array in firebase.firestore.CollectionReference | firebase.firestore.Query why?
body: <pre><code>const list = this.afs.collection( 'City').ref;
  let queryCollection: firebase.firestore.CollectionReference | firebase.firestore.Query &amp; Array = list;
  
  for (let _i = 0; _i &lt; this.data.areaList.length; _i++) {
  
      if (this.data.areaList) {  
          queryCollection[_i] = queryCollection.where('areaList', '==', this.data.areaList[_i]);
      }
      console.log(this.data.areaList[_i]);
  }
  </code></pre>
  
  <p>Note: can't use let only const why and how to change error ?
  I wanna use let queryCollection .
  <a href="https://i.stack.imgur.com/3R5tD.png" rel="nofollow noreferrer">I wanna create advanced Firestore data filter</a></p>