In this guide, I will explain how to use the $currentDate operator in MongoDB.
The $currentDate operator in MongoDB allows users to set a field’s value as the current date. The value by default is of Date type however, you can even set a timestamp type value by explicitly stating it.
This guide will walk you through the easiest way to set a current date value using the $currentDate operator in MongoDB. So, let us get this amazing guide started!
Table of Contents
The $currentDate Operator Syntax in MongoDB
Let us take a quick look at the $currentDate syntax in MongoDB when using in the mongo shell.
{ $currentDate: { field1: typeSpecification1, … } }
We must set the $currentDate as true to allow the operator to set the current date as its operator. To specify the type of date value, you can state as { $type: “timestamp” } or { $type: “date” } as per your needs. Make sure you only use lowercase letters as the operator is case sensitive.
Also, if a given field does not exist, the operator adds it by itself and sets the value as the current date.
Using the $currentDate Operator in MongoDB
Let us get started with using the $currentDate operator in MongoDB.
Before we proceed let me list out all the documents of cats collection that I am going to work with.
> db.cats.find().pretty()
{
"_id" : ObjectId("602eb6c728ff814b64eb3411"),
"name" : "Stephanie",
"age" : 22,
"breed" : "Persian Cat",
"personality" : {
"dogFriendly" : true,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb73728ff814b64eb3412"),
"name" : "Whiskers",
"age" : 4,
"breed" : "Scottish Fold",
"personality" : {
"dogFriendly" : false,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb84628ff814b64eb3413"),
"name" : "Krissy",
"age" : 6,
"breed" : "Turkish Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc5ea78db75e09057cd0"),
"name" : "Cassy",
"age" : 16,
"breed" : "Japanese Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc9da78db75e09057cd1"),
"name" : "Shane",
"age" : 11,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebed7a78db75e09057cd2"),
"name" : "Phoebe",
"age" : 21,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
This is the collection I am going to work with.
Using the $currentDate Operator with a Non-Existent Embedded Field
In the example, I want to insert an embedded document that doesn’t exist in our collection. Let’s say I want to set an adoptionDate field inside the moreDetails field because all our cats got adopted today:
> db.cats.updateMany({}, {$currentDate: {"moreDetails.adoptionDate": true}})
{ "acknowledged" : true, "matchedCount" : 6, "modifiedCount" : 6 }
> db.cats.find().pretty()
{
"_id" : ObjectId("602eb6c728ff814b64eb3411"),
"name" : "Stephanie",
"age" : 22,
"breed" : "Persian Cat",
"personality" : {
"dogFriendly" : true,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.933Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb73728ff814b64eb3412"),
"name" : "Whiskers",
"age" : 4,
"breed" : "Scottish Fold",
"personality" : {
"dogFriendly" : false,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.938Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb84628ff814b64eb3413"),
"name" : "Krissy",
"age" : 6,
"breed" : "Turkish Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.938Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc5ea78db75e09057cd0"),
"name" : "Cassy",
"age" : 16,
"breed" : "Japanese Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.938Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc9da78db75e09057cd1"),
"name" : "Shane",
"age" : 11,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.939Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebed7a78db75e09057cd2"),
"name" : "Phoebe",
"age" : 21,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.939Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
Setting a Date or Timestamp Using the $currentDate Operator
We will set a date type in this example.
Setting a Date type
> db.cats.updateMany({}, {$currentDate: {"moreDetails.adoptionDate": {$type: "date"}}})
{ "acknowledged" : true, "matchedCount" : 6, "modifiedCount" : 6 }
> db.cats.find().pretty()
{
"_id" : ObjectId("602eb6c728ff814b64eb3411"),
"name" : "Stephanie",
"age" : 22,
"breed" : "Persian Cat",
"personality" : {
"dogFriendly" : true,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.933Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb73728ff814b64eb3412"),
"name" : "Whiskers",
"age" : 4,
"breed" : "Scottish Fold",
"personality" : {
"dogFriendly" : false,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.938Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb84628ff814b64eb3413"),
"name" : "Krissy",
"age" : 6,
"breed" : "Turkish Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.938Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc5ea78db75e09057cd0"),
"name" : "Cassy",
"age" : 16,
"breed" : "Japanese Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.938Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc9da78db75e09057cd1"),
"name" : "Shane",
"age" : 11,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.939Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebed7a78db75e09057cd2"),
"name" : "Phoebe",
"age" : 21,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : ISODate("2021-10-28T21:47:06.939Z")
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
The output doesn’t seem any different as the Date type is the default and hence the $currentDate operator spits the same value.
Setting a Timestamp Type
> db.cats.updateMany({}, {$currentDate: {"moreDetails.adoptionDate": {$type: "timestamp"}}})
{ "acknowledged" : true, "matchedCount" : 6, "modifiedCount" : 6 }
> db.cats.find().pretty()
{
"_id" : ObjectId("602eb6c728ff814b64eb3411"),
"name" : "Stephanie",
"age" : 22,
"breed" : "Persian Cat",
"personality" : {
"dogFriendly" : true,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : Timestamp(1635457867, 1)
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb73728ff814b64eb3412"),
"name" : "Whiskers",
"age" : 4,
"breed" : "Scottish Fold",
"personality" : {
"dogFriendly" : false,
"childFriendly" : true
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : Timestamp(1635457867, 2)
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602eb84628ff814b64eb3413"),
"name" : "Krissy",
"age" : 6,
"breed" : "Turkish Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : Timestamp(1635457867, 3)
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc5ea78db75e09057cd0"),
"name" : "Cassy",
"age" : 16,
"breed" : "Japanese Angora",
"personality" : {
"dogFriendly" : true,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : Timestamp(1635457867, 4)
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebc9da78db75e09057cd1"),
"name" : "Shane",
"age" : 11,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : Timestamp(1635457867, 5)
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
{
"_id" : ObjectId("602ebed7a78db75e09057cd2"),
"name" : "Phoebe",
"age" : 21,
"breed" : "Bobtail",
"personality" : {
"dogFriendly" : false,
"childFriendly" : false
},
"moreDetails" : {
"cost" : 30000,
"adoptionDate" : Timestamp(1635457867, 6)
},
"likes" : [
"fish",
"milk",
"chicken",
"blankets"
]
}
Conclusion
In this article, we learned to use the $currentDate operator in MongoDB. Learn more about MongoDB and NodeJS on CodeForGeeks.com
Noteworthy References
https://docs.mongodb.com/manual/reference/operator/update/currentDate/