MuleSoft DataWeave Part -3

2 min readApr 8, 2024

In this blog, I’d like to walk you through various transformations that can be performed in DataWeave like zip, unzip, flatten etc

Zip :

Merges elements from two arrays into an array of arrays.

Syntax :

zip<T, R>(left: Array<T>, right: Array<R>): Array<Array<T | R>>

left : The array on the left-hand side of the function.

right : The array on the right-hand side of the function.

We have two arrays namely employeeNames and country they belong to. Here the idea is to group the employee with their country in one array, for this we will use zip function

DataWeave syntax

%dw 2.0
output application/json
var employeeNames = ["Mridul", "Piotr", "John"]
var country = ["IN","PL","CA"]
---
{
    employeeDetails : zip (employeeNames, country),
   // employeeDetails : employeeNames zip country (Both are same)
}

Output

Unzip :

It takes an array of arrays as input and does the opposite of zip function

Syntax :

unzip<T>(items: Array<Array<T>>): Array<Array<T>>

DataWeave Syntax :

%dw 2.0
output application/json
var employeeNames = ["Mridul", "Piotr", "John"]
var country = ["IN","PL","CA"]
---
{
    employeeDetails : unzip(zip (employeeNames, country))
}

Output

Example 2 :

Flatten :

Convert the array of arrays into a single array with all values.

Syntax :

flatten<T, Q>(@StreamCapable items: Array<Array<T> | Q>): Array<T | Q>

Dataweave :

%dw 2.0
output application/json
var fruits = [
                  [
                     "fruit" : "orange",
                     "fruit" : "apple"
                  ],
                  [
                     "fruit" : "grape",
                     "fruit" : "kiwi"
                  ]
               ]
---
{
    FruitInfo: flatten (fruits)
}

Output