flattenDeep: Function to get an array flattened recursively by sublevels

[VictorManhani]

We often have the need to flatten an array of arrays. However, there are cases where it is necessary to convert an array of multi-level arrays, but DataWeave does not have an out-of-the-box function for this, nor an easy solution that solves the scenarios where the sub-levels are composed with Array and Range. And besides, I miss setting the flattening level in the sublevels.

So we thought and created a function to facilitate our planning with these features and improvements. The name of this function is flattenDeep containing two input parameters, the 1st parameter being the array of elements and the 2nd parameter the flattening level. Here is the example of the function:

%dw 2.0
output application/json

fun flattenDeep(arr: Array, level: Number) = arr flatMap (if ((typeOf($) matches /Range|Array/) and level > 0) flattenDeep($, level - 1) else [$])

var arrLevels = [0,9,3.1,[1,'¬',[3,'4', ['a','b', (1 to 3), ['açaí', 'banana', 'chocolate', [134]], null], true, false], {}], {"name": "Ronaldo", "codename": "Victor"}]
---
flattenDeep(arrLevels, 4)
// arrLevels flattenDeep 4

Expected Output:

[
	0,
	9,
	3.1,
	1,
	"¬",
	3,
	"4",
	"a",
	"b",
	1,
	2,
	3,
	"açaí",
	"banana",
	"chocolate",
	[134],
	null,
	true,
	false,
	{},
	{
		"name": "Ronaldo",
		"codename": "Victor"
	}
]