Cloud Firestore collection count

Question

Is it possible to count how many items a collection has using the new Firebase database, Cloud Firestore?

If so, how do I do that?

Answer 1

There is no direct option available. You cant't do db.collection("CollectionName").count(). Below are the two ways by which you can find the count of number of documents within a collection.

1 :- Get all the documents in the collection and then get it's size.(Not the best Solution)

db.collection("CollectionName").get().subscribe(doc=>{
console.log(doc.size)
})

By using above code your document reads will be equal to the size of documents within a collection and that is the reason why one must avoid using above solution.

2:- Create a separate document with in your collection which will store the count of number of documents in the collection.(Best Solution)

db.collection("CollectionName").doc("counts")get().subscribe(doc=>{
console.log(doc.count)
})

Above we created a document with name counts to store all the count information.You can update the count document in the following way:-

• Create a firestore triggers on the document counts
• Increment the count property of counts document when a new document is created.
• Decrement the count property of counts document when a document is deleted.

w.r.t price (Document Read = 1) and fast data retrieval the above solution is good.