Array Operators

Operator	Description	Example
$size	Returns the size of the array argument. The argument must resolve to an array	{“$size”: “body”}
$slice	Returns the subset of an array. Param 1: The master array Param 2 (optional): the position to start evaluating the array from Param 3: the number of elements from param 2 to return	{ $slice: [ [ 1, 5, 7, 9 ], 1, 2 ] } // returns [5, 7]
$isArray	Returns true if the operand is an array	{"$isArray": [1,2,3]} // returns true
$concatArrays	Returns an array which contains all the arrays concatenated together.	{"$concatArrays": [ [ "medable", "is"], [ "great" ] ] } //returns ["medable", "is", "great"]
$arrayElemAt	Returns the element in the array at a specified index.	{ $arrayElemAt: [ [ "purple", "orange", "yellow" ], 1 ] } //returns "orange"