In MongoDB, the cursor.map() method applies a function to each document visited by the cursor and combines the return values in an array.
Author: Ian
MongoDB $isNumber
From MongoDB 4.4, you can use the $isNumber aggregation pipeline operator to check whether or not a value is a number.
It accepts any valid expression, and returns true if the expression is a number, false if it’s not.
MongoDB $replaceAll
The $replaceAll aggregation pipeline operator was introduced in MongoDB 4.4.
This operator replaces all instances of a search string in an input string with a replacement string and returns the result.
If the search string isn’t found, then $replaceAll returns the input string.
MongoDB $replaceOne
The $replaceOne aggregation pipeline operator was introduced in MongoDB 4.4.
This operator replaces the first instance of a search string in an input string with a replacement string and returns the result.
If the search string isn’t found, then $replaceOne returns the input string.
MongoDB $last Aggregation Pipeline Operator
MongoDB 4.4 introduced the $last aggregation pipeline operator.
This operator returns the last element in an array.
Continue readingMongoDB $first Aggregation Pipeline Operator
MongoDB 4.4 introduced the $first aggregation pipeline operator.
This operator returns the first element in an array.
Continue readingMongoDB $arrayElemAt
In MongoDB, the $arrayElemAt aggregation pipeline operator returns the element at the specified array index.
It accepts two arguments;
- The array
- The index of the element you want to retrieve
MongoDB $bsonSize
From MongoDB 4.4, you can use the $bsonSize aggregation pipeline operator to return the size of a given document in bytes.
$bsonSize accepts any valid expression as long as it resolves to either an object or null.
MongoDB Object.bsonSize()
In MongoDB, you can use the Object.bsonSize() method to return the size of a document in bytes.
MongoDB $binarySize
From MongoDB 4.4, you can use the $binarySize aggregation pipeline operator to return the size of a given string or binary data value’s content in bytes.
It accepts any valid expression as long as it resolves to either a string or binary data value. The argument can also be null, in which case, $binarySize returns null.