Check if Firestore document exists and return boolean

user_16816004 0
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I want to make a utility function that returns true or false depending on whether a firestore document in a collection exists.

Below is what I originally wrote, but it returns a promise instead of a boolean.

async function docExists(docName, docId) {
  const docRef = db.collection(docName).doc(docId);

  await docRef.get().then((docSnapshot) => {
    if (docSnapshot.exists) {
      return true
    } else {
      return false
    }
  });
}

Is there a way for it to return a boolean, or is this just the wrong way to approach the problem?

promise google-cloud-firestore firebase javascript
2 Answers

There's no need to mix the await and .then syntax like you have in your question. This should be sufficient:

async function docExists(docName, docId) {
  const docRef = db.collection(docName).doc(docId);

  let docSnapshot = await docRef.get();
  
  if (docSnapshot.exists) {
    return true;
  } else {
    return false;
  }
}

Alternatively, through the use of promise chaining, you should be able to simply add the return keyword before the original await docRef.get().then(...) that you have in your question.

user_15413970

A simple one liner for that could be:

const docExists = async (docName, docId) => (await db.collection(docName).doc(docId).get()).exists
user_131306970
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