Mule 4 DataWeave(1.x) Script To Resolve Wildcard Dynamically

DataWeave is a powerful programming language designed and supported by MuleSoft in Mule applications. In Mule runtime version 4.x, DataWeave version 2.0 is supported. The internal DWL version could be different; however, in the script, %dwl 2.0 needs to be defined. It is mainly used for transforming and accessing data in the Mule flow relating to several components such as connectors and transformers.

In this article, we are trying to resolve a wildcard dynamically using a user-defined DataWeave function. In DWL 2.0, I could not find any core function or operator present to support the feature; hence, I decided to write one. An article for the same use case for Mule 3 with Dataweave 1.0 is already published on DZone.

Goal To Achieve Below

Input: "This is to test wildcards.1st wildcard {1}, 2nd wildcard {2}, Nth wildcard {n}"
Output: "This is to test wildcards.1st wildcard 1, 2nd wildcard 2, Nth wildcard Wn"
  Assuming passing set of wildcards as [1,2,"Wn"]

DataWeave(2.0) Code

%dw 2.0
output application/json

var inputString = "This is to test wildcards.1st wildcard {1}, 2nd wildcard {2}, Nth wildcard {n}"
fun resolveParam(unresolvedString,parameters=[]) =
	do {
    var propArr=unresolvedString splitBy /\{\w*\}/ 
	---
		if (sizeOf(propArr)  > 1 ) (flatten (propArr zip parameters) reduce ($$ ++ $)) else (unresolvedString)
    }
---
resolveParam(inputString,[1,2,"Wn"])

Explanation

Here in DWL 2.0, a function named resolveParam can accept two parameters: unresolvedString (mandatory), and parameters (optional: with default empty array value when no wildcard replacement is required). In this function, logic unresolvedString split into an array of strings based on a regex \{\w*\} that matches {<anystring_without_special_character>}.The results were that the array was then zipped with input parameters using those wildcards that needed to be replaced in the same order.  Lastly, using reduce and "++" operator, the final wildcard was resolved and the string prepared.

I hope this will help to achieve your goal. The Mule 4 DWL 2.0 function was created separately to create less confusion as Mule 3 DWL 1.0 is still being used in a large group of organizations.