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Date() and Datetime

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  • Compatibility
  • Syntax
  • Behavior
  • Examples
Date()

Returns a date either as a string or as a Date object. The date can contain a date and a time, known as a datetime.

The BSON specification states a Date object contains the UTC datetime. UTC is Coordinated Universal Time. The UTC datetime stores an unsigned 64-bit integer value, indicating the number of milliseconds after the Unix epoch (January 1st, 1970 at 00:00:00 UTC).

Compatibility

You can use Date() for deployments hosted in the following environments:

  • MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

Syntax

You can specify either of the following formats:

  • Date() returns the current date as a string in mongosh.

  • new Date() returns the current date as a Date object. mongosh wraps the Date object with the ISODate helper. The ISODate is in UTC.

You can specify a particular date by passing an ISO-8601 date string with a year within the inclusive range 0 through 9999 to the new Date() constructor or the ISODate() function. These functions accept the following formats:

  • new Date("<YYYY-mm-dd>") returns the ISODate with the specified date.

  • new Date("<YYYY-mm-ddTHH:MM:ss>") specifies the datetime in the client's local timezone and returns the ISODate with the specified datetime in UTC.

  • new Date("<YYYY-mm-ddTHH:MM:ssZ>") specifies the datetime in UTC and returns the ISODate with the specified datetime in UTC.

  • new Date(<integer>) specifies the datetime as milliseconds since the UNIX epoch (Jan 1, 1970), and returns the resulting ISODate instance.

Behavior

Internally, Date objects are stored as a signed 64-bit integer representing the number of milliseconds since the Unix epoch (Jan 1, 1970).

Not all database operations and drivers support the full 64-bit range. You may safely work with dates with years within the inclusive range 0 through 9999.

Examples

Use Date in a Query

If no document with _id equal to 1 exists in the products collection, the following operation inserts a document with the field dateAdded set to the current date:

db.products.updateOne(
   { _id: 1 },
   {
     $set: { item: "apple" },
     $setOnInsert: { dateAdded: new Date() }
   },
   { upsert: true }
)

Tip

See also:

Return Date as a String

To return the date as a string, use the Date() method. For example:

var myDateString = Date();

Return Date as Date Object

mongosh wraps objects of Date type with the ISODate helper. However, the objects are Date types.

The following example uses new Date() to return a Date object with the specified UTC datetime:

var myDate = new Date("2016-05-18T16:00:00Z");

Tip

See also:

Insert and Return ISODate Objects

You can specify dates as ISODate objects.

The following example creates a cakeSales collection with ISODate objects in the orderDate field:

db.cakeSales.insertMany( [
   { _id: 0, type: "chocolate", orderDate: new ISODate("2020-05-18T14:10:30Z") },
   { _id: 1, type: "strawberry", orderDate: new ISODate("2021-03-20T11:30:05Z") },
   { _id: 2, type: "vanilla", orderDate: new ISODate("2021-01-15T06:31:15Z") }
] )

The following example returns documents where the orderDate is less than the ISODate specified in the $lt operator:

db.cakeSales.find( { orderDate: { $lt: ISODate("2021-02-25T10:03:46.000Z") } } )

Example output:

[
   {
      _id: 0,
      type: 'chocolate',
      orderDate: ISODate("2020-05-18T14:10:30.000Z")
   },
   {
      _id: 2,
      type: 'vanilla',
      orderDate: ISODate("2021-01-15T06:31:15.000Z")
   }
]

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