Top DataWeave Functions for Data Transformation | MuleSoft Guide

Converts a string to uppercase. Learn key concepts, integration patterns, and MuleSoft best practices.

Below are some examples of DataWeave functions along with their input and output.

1. upper

Converts a string to uppercase.

Input:

{  "text": "hello world"}

DataWeave Code:

%dw 2.0output application/json---upper(payload.text)

Output:

"HELLO WORLD"

---

2. lower

Converts a string to lowercase.

Input:

{  "text": "HELLO WORLD"}

DataWeave Code:

%dw 2.0output application/json---lower(payload.text)

Output:

"hello world"

---

3. sizeOf

Returns the size of an array or string.

Input:

{  "array": [1, 2, 3, 4, 5]}

DataWeave Code:

%dw 2.0output application/json---sizeOf(payload.array)

Output:

5

---

4. filter

Filters an array based on a condition.

Input:

{  "numbers": [1, 2, 3, 4, 5]}

DataWeave Code:

%dw 2.0output application/json---payload.numbers filter ((item) -> item > 2)

Output:

[3, 4, 5]

---

5. map

Transforms each element in an array.

Input:

{  "numbers": [1, 2, 3]}

DataWeave Code:

%dw 2.0output application/json---payload.numbers map ((item) -> item * 2)

Output:

[2, 4, 6]

6. join

Joins elements of an array into a string.

Input:

{  "words": ["Hello", "World"]}

DataWeave Code:

%dw 2.0output application/json---payload.words joinBy(" ")

Output:

"Hello World"

---

7. mapObject

Transforms each key-value pair in an object.

Input:

{  "object": {"a": 1, "b": 2}}

DataWeave Code:

%dw 2.0output application/json---payload.object mapObject((value, key) -> (key ++ "_new"): value * 2)

Output:

{"a_new": 2, "b_new": 4}

---

8. pluck

Extracts the values of a specific key from an array of objects.

Input:

{  "people": [{"name": "Alice"}, {"name": "Bob"}]}

DataWeave Code:

%dw 2.0output application/json---payload.people pluck("name")

Output:

["Alice", "Bob"]

---

9. contains

Checks if an array contains a specific element.

Input:

{  "array": [1, 2, 3, 4, 5],  "value": 3}

DataWeave Code:

%dw 2.0output application/json---payload.array contains(payload.value)

Output:

true

---

10. reduce

Reduces an array to a single value using a provided accumulator function.

Input:

{  "numbers": [1, 2, 3, 4]}

DataWeave Code:

%dw 2.0output application/json---payload.numbers reduce ((item, acc = 0) -> acc + item)

Output:

10

---

11. distinct

Returns distinct elements from an array.

Input:

{  "numbers": [1, 2, 2, 3, 4, 4]}

DataWeave Code:

%dw 2.0output application/json---payload.numbers distinct($)

Output:

[1, 2, 3, 4]

---

12. sum

Returns the sum of an array of numbers.

Input:

{  "numbers": [1, 2, 3, 4]}

DataWeave Code:

%dw 2.0output application/json---sum(payload.numbers)

Output:

10

---

13. find

Finds the first element that matches a condition.

Input:

{  "numbers": [1, 2, 3, 4, 5]}

DataWeave Code:

%dw 2.0output application/json---payload.numbers find 3

Output:

2

---

These examples demonstrate how to use core functions in DataWeave to manipulate and transform data effectively. If you have a specific function or use case in mind, feel free to comment!

]]>