Map Function in DataWeave:
The map function in DataWeave is used to transform an array of elements by applying a function to each element. The function takes an element as input and returns a new element, which is then added to the new array. Here’s an example:
%dw 2.0
output application/json
---
[1, 2, 3] map (item) -> item * 2
In this example, the map function takes an array of numbers [1, 2, 3] and multiplies each element by 2, resulting in a new array [2, 4, 6].
FlatMap Function in DataWeave:
The flatMap function in DataWeave is used to transform an array of elements into a new array by applying a function that returns an array for each element. The resulting arrays are then combined into a single array. Here’s an example:
%dw 2.0
output application/json
---
[1, 2, 3] flatMap (item) -> [item, item * 2]
In this example, the flatMap function takes an array of numbers [1, 2, 3] and for each element, it returns an array containing the element and its double [1, 2], [2, 4], [3, 6]. These arrays are then combined into a single array [1, 2, 2, 4, 3, 6].
Differences between Map and FlatMap in DataWeave:
Output type:
The map function returns an array of the same length as the input array, while the flatMap function can return an array of a different length, depending on the function used.
Function input and output:
The map function takes an element as input and returns a single element as output, while the flatMap function takes an element as input and returns an array of elements as output.
Nested arrays:
The map function does not handle nested arrays, while the flatMap function can be used to flatten nested arrays.
Data structure:
The map function is best used for transforming simple data structures, while the flatMap function is better suited for more complex data structures that require flattening.
In conclusion, the map and flatMap functions in DataWeave are powerful tools for transforming data. While both functions are used to transform arrays, the key difference between them lies in their output type and their handling of nested arrays. Understanding the differences between these functions will help developers to choose the right function for their data transformation needs.