How to query a Firestore collection for documents added today

Caveats

This example assumes that each document in your collection has a date field. I'm also using the Firebase Admin SDK since this code is run in a Firebase Function.

I have a date field on each of the documents in my notes collection.

Helper function

In the getStartOfToday function below, first we get today's date using new Date(). Then we set it to midnight of today, convert it to a timestamp, and return the timestamp.

function getStartOfToday() {
  const now = new Date()
  now.setHours(5, 0, 0, 0) // +5 hours for Eastern Time
  const timestamp = admin.firestore.Timestamp.fromDate(now)
  return timestamp // ex. 1631246400
}

Note: I had to add 5 hours to get EST. You might want to tweak this and test yourself. 🤷‍♂️

Querying the notes collection

As you can see below, with the getStartOfToday function we can run a Firestore query and ask for all documents that have a timestamp greater than the beginning of today. This will return only the documents that have a timestamp from today assuming your date field is of type Timestamp. Woot! 🎊

const snapshot = await admin
  .firestore()
  .collection('notes')
  .where('date', '>', getStartOfToday())
  .get()
const notes = snapshot.docs.map((doc) => doc.data())

All Together

function getStartOfToday() {
  const now = new Date()
  now.setHours(5, 0, 0, 0) // +5 hours for Eastern Time
  const timestamp = admin.firestore.Timestamp.fromDate(now)
  return timestamp // ex. 1631246400
}

const snapshot = await admin
  .firestore()
  .collection('notes')
  .where('date', '>', getStartOfToday())
  .get()
const notes = snapshot.docs.map((doc) => doc.data())