Select Firebase firestore 集合，其中时间戳为今天

Question

Good day everybody,

I have a firetore collection of docs which all have a dateCreated field of timestamp data type. I want to select all the docs where dateCreated is today. How would I achieve this. I have tried below with no success

const ref = firestore.collection('orders').where('dateCreated','<',moment().toDate()).orderBy('dateCreated', 'desc');

The above line gets all the orders from the collection and I want all the orders that was created today. Hope this makes sense

Thanks Everyone

Answer 1

If you are talking relative to the user's own timezone and not based on a fixed timezone (eg you are on the east coast, but HQ is on the west coast), you can use this:

// for numeric timestamp values (milliseconds since 1970-01-01 UTC)
const midnightThisMorning = (new Date()).setHours(0,0,0,0);

const ref = firestore.collection('orders')
  .where('dateCreated', '>', midnightThisMorning)
  .orderBy('dateCreated', 'desc');

// for firebase.firestore.Timestamp values
const startDate = new Date();
startDate.setHours(0,0,0,0);

const ref = firestore.collection('orders')
  .where('dateCreated', '>', startDate)
  .orderBy('dateCreated', 'desc');

If you know that the time must be relative to a particular timezone, you need to calculate midnight based on that timezone instead.

// for numeric timestamp values (milliseconds since 1970-01-01 UTC)
const midnightInLA = moment()
  .tz("America/Los_Angeles")
  .startOf("day")
  .valueOf();

const ref = firestore.collection('orders')
  .where('dateCreated', '>', midnightInLA)
  .orderBy('dateCreated', 'desc');

// for firebase.firestore.Timestamp values
const dateMidnightInLA = moment()
  .tz("America/Los_Angeles")
  .startOf("day")
  .toDate();

const ref = firestore.collection('orders')
  .where('dateCreated', '>', dateMidnightInLA)
  .orderBy('dateCreated', 'desc');

Note: With moment-timezone , if you are only using select timezones you can deploy your code with the details for those timezones rather than all timezones. This process is detailed in the documentation .