How to use $type in MongoDB?

The $type selects documents where the value of the field is an instance of the specified BSON type. Let us create a collection with documents −

> db.demo615.insert({"Value":100});
WriteResult({ "nInserted" : 1 })
> db.demo615.insert({"Value":"100"});
WriteResult({ "nInserted" : 1 })
> db.demo615.insert({"Value":"300"});
WriteResult({ "nInserted" : 1 })
> db.demo615.insert({"Value":300});
WriteResult({ "nInserted" : 1 })

Display all documents from a collection with the help of find() method −

> db.demo615.find();

This will produce the following output −

{ "_id" : ObjectId("5e99bb3465492f6c60d0027f"), "Value" : 100 }
{ "_id" : ObjectId("5e99bb3865492f6c60d00280"), "Value" : "100" }
{ "_id" : ObjectId("5e99bb3c65492f6c60d00281"), "Value" : "300" }
{ "_id" : ObjectId("5e99bb4265492f6c60d00282"), "Value" : 300 }

Following is the query to use MongoDB find without a hexadecimal _id −

> db.demo615.find({ "Value" : { $type : "string"} } );

This will produce the following output −

{ "_id" : ObjectId("5e99bb3865492f6c60d00280"), "Value" : "100" }
{ "_id" : ObjectId("5e99bb3c65492f6c60d00281"), "Value" : "300" }