$currentDate¶

Definition¶

$currentDate¶

The $currentDate operator sets the value of a field to the current date, either as a Date or a timestamp. The default type is Date.

The $currentDate operator has the form:

{ $currentDate: { <field1>: <typeSpecification1>, ... } }

<typeSpecification> can be either:

a boolean true to set the field value to the current date as a Date, or
a document { $type: "timestamp" } or { $type: "date" } which explicitly specifies the type. The operator is case-sensitive and accepts only the lowercase "timestamp" or the lowercase "date".

To specify a <field> in an embedded document or in an array, use dot notation.

Behavior¶

If the field does not exist, $currentDate adds the field to a document.

Example¶

Consider the following document in the users collection:

{ _id: 1, status: "a", lastModified: ISODate("2013-10-02T01:11:18.965Z") }

The following operation updates the lastModified field to the current date, the``”cancellation.date”`` field to the current timestamp as well as updating the status field to "D" and the "cancellation.reason" to "user request".

db.users.update(
   { _id: 1 },
   {
     $currentDate: {
        lastModified: true,
        "cancellation.date": { $type: "timestamp" }
     },
     $set: {
        status: "D",
        "cancellation.reason": "user request"
     }
   }
)

The updated document would resemble:

{
   "_id" : 1,
   "status" : "D",
   "lastModified" : ISODate("2014-09-17T23:25:56.314Z"),
   "cancellation" : {
      "date" : Timestamp(1410996356, 1),
      "reason" : "user request"
   }
}