Introduction to MongoDB cursor.hasNext() Method

In MongoDB, the cursor.hasNext() method is used to check if there is another document available in the cursor. It returns true if there is, and false if there isn’t.

Syntax

The syntax for cursor.hasNext() is as follows: cursor.hasNext()

Usage

db.collection.find().hasNext()

It is useful when we need to process each document in a query result set one by one.

Example

Suppose we have a collection called students that contains the following documents:

{ "_id" : 1, "name" : "Alice", "age": 20 }
{ "_id" : 2, "name" : "Bob", "age": 25 }
{ "_id" : 3, "name" : "Charlie", "age": 30 }

We can use the find() method to query for all the documents:

const cursor = db.students.find()

Then, we can use cursor.hasNext() to iterate through each document and print its contents:

while (cursor.hasNext()) {
  const doc = cursor.next()
  printjson(doc)
}

The output will be:

{ "_id" : 1, "name" : "Alice", "age": 20 }
{ "_id" : 2, "name" : "Bob", "age": 25 }
{ "_id" : 3, "name" : "Charlie", "age": 30 }

Conclusion

The cursor.hasNext() method is useful for checking if there are more documents available in a cursor. It is commonly used for iterating through documents in a query result set.