How do you define and call a function in DataWeave 2.0?

• A. Define with the function keyword in the header (e.g., %dw 2.0, ... functionName(params) = ...); call by name with arguments.
• B. Define with the def keyword, and call using call functionName(params).
• C. Functions are not allowed in DataWeave 2.0; only modules can be imported.
• D. Function definitions require a separate schema file; call by index.

Answer: (D)

In DataWeave 2.0 you define reusable logic using the fun keyword and call it by its name with arguments. You can place a named function at the top level of your script or inside a module, then invoke it just like any other function by writing its name followed by parentheses with the needed parameters. For example, define a function to greet someone, then call it with a name. You can also create anonymous functions and assign them to a variable, then call the variable like a function. If you work with imported modules, you call the exported functions from those modules by their names as well. There’s no need for a separate schema file, and you don’t call by index; you call by the function’s identifier.