ObjectId
Description
ObjectId
() Returns a new ObjectId value. The 12-byte ObjectIdvalue consists of:
- a 4-byte value representing the seconds since the Unix epoch,
- a 5-byte random value, and
- a 3-byte counter, starting with a random value.
ObjectId()
can accept the following parameter:
FieldTypeDescriptionhexadecimal
StringOptional. Hexadecimal string value for the new ObjectId.
Methods and Attributes
ObjectId()
has the following attribute and methods:
Attribute/Method | Description |
---|---|
str | Returns the hexadecimal string representation of the object. |
ObjectId.getTimestamp() | Returns the timestamp portion of the object as a Date. |
ObjectId.toString() | Returns the JavaScript representation in the form of a stringliteral “ObjectId(…) ”. |
ObjectId.valueOf() | Returns the representation of the object as a hexadecimalstring. The returned string is the str attribute. |
Examples
Generate a New ObjectId
To generate a new ObjectId, use ObjectId()
with no argument:
- x = ObjectId()
In this example, the value of x
would be:
- ObjectId("507f1f77bcf86cd799439011")
Specify a Hexadecimal String
To generate a new ObjectId using ObjectId()
with a uniquehexadecimal string:
- y = ObjectId("507f191e810c19729de860ea")
In this example, the value of y
would be:
- ObjectId("507f191e810c19729de860ea")
Access the Hexadecimal String
Access the str
attribute of an ObjectId()
object, as follows:
- ObjectId("507f191e810c19729de860ea").str
This operation will return the following hexadecimal string:
- 507f191e810c19729de860ea
See also