Why firestore does not return object when using where clause in chrome extension?

user_4008722 0
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I'm trying to filter some data from Firestore using chrome extension. My first code block works and gives the ch_id, but the second (filtered with where clause) is not returning object.

First code block. This works properly and gives message doc.data().ch_id as "ch001".

svrGetVids("ch001");
function svrGetVids(ch_id)
{
   try{
    var docRef = db.collection("channel")
    .doc("000000000000000000000001");
    docRef.get().then(function(doc) {
        if (doc.exists) {
            alert( doc.data().ch_id);
        } else {
            alert('no doc found');
        }
    }).catch(function(error) {
        alert(error.message);
    });
}catch(error)
{
    alert(error.message);
}

/*second code block. This does not return the object, and alerts 'no doc found'*/

 try{
    db
    .collection("channel")
    .where("ch_id",'==', ch_id)
    .get()
    .then(function(doc) {
        if (doc.exists) {
            alert( doc.data().ch_id);        
        } else {
            alert('no doc found');
        }
    }).catch(function(error) {
        alert('e1'+error.message);
    });
  }catch(error)
  {
     alert('e2'+error.message);
  }
}

Can anyone please find what I'm doing wrong in the second code block?

google-cloud-firestore google-chrome-extension javascript
1 Answers

The reason is because there is a difference between the type of the object you are getting. The docRef.get() returns a DocumentSnapshot while db.collection("channel").where("ch_id",'==', ch_id).get() returns a QuerySnapshot, which does not have a exists property, as you can see in the documentation.

So if you want the same result, you will have to do something like this:

try{
    db.collection("channel")
      .where("ch_id",'==', ch_id)
      .get()
      .then(function(querySnapshot) {
          if (!querySnapshot.empty) {
              querySnapshot.foreach(function(doc) {
                  alert(doc.data().ch_id);        
              });
          } else {
              alert('no doc found');
          }
    }).catch(function(error) {
        alert('e1'+error.message);
    });
  }catch(error)
  {
     alert('e2'+error.message);
  }
user_128577030
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