Functions in DataWeave 2.0

Functions are one of DataWeave’s most important tools.

You can define your own DataWeave functions using the fun declaration in the header of a DataWeave script. In this section we will cover these topics around functions:

Named functions
Lambdas
Passing functions to other functions
Calling 2-arity functions with infix notation
$, $$, $$$ syntax

To define a function in DataWeave use the following syntax:

fun myFunction(param1, param2, ...) = <code to execute>

The fun keyword starts the definition of a function.
myFunction is the name you define for the function. Function names must be valid identifiers. For additional details about valid identifiers, see Rules for Declaring Valid Identifiers.
(param1, param2, … , paramn) represents the parameters that your function accepts. You can specify from zero to any number of parameters, separated by commas (,) and enclosed in parentheses.
The = sign marks the beginning of the code block to execute when the function is called.
<code to execute> represents the actual code that you define for your function.