Why are non auto-generated document Ids are in ita

问题:

When i add a document with my own document Id (not auto generated), document Id node is in italics as shown in the screenshot from Firestore console. What is the reason behind this?

My code to add data is

const billingRef = db
      .collection('billing/test/2017/months/11')
      .doc();

  billingRef
      .set({ name: 'ABC' })
      .then(_ => {
        console.log('saved');
      })
      .catch(err => {
        console.log(err);
      });

Above code adds a node successfully, but adds node "test" and "months" in italics.

screenshot 1

screenshot 2 screenshot 3

My query yields zero results for such records in firestore, following code. How can I query all the nodes under billing?

db.collection("billing").get().then(function(querySnapshot) {
    console.log(querySnapshot.size) // this is always 0
    querySnapshot.forEach(function(doc) {
        console.log(doc.id, " => ", doc.data());
    });
});

回答1:

Following up on my comment above you will see in the Firestore console that for Documents in italic there is a small text saying "This document does not exist, it will not appear in queries or snapshots", for non-italic it says "This document has no data", so the intuition is that when the Document is created in code without any Fields then it is "null" (a subcollection does not count). If a Field is added and removed, then the Document is simply empty and not null.

Since your query for the Documents under billing are in italic ("null" or does not exist), as the text above states, they will not appear in queries.

The solution would be to either add the document through the Firestore console because here Documents are created as empty, or if in code, add a Field and maybe remove it again if not needed, then the Documents will appear in queries.