%dw 2.0
var arrayOne = [
[
"keyOne" : 1,
"keyTwo" : 2
],
[
"keyThree" : 3,
"keyFour" : 4,
"keyFive" : 5
],
"keySix" : 6
]
output application/json
---
flatten(arrayOne)
Flatten Elements of Arrays
DataWeave can flatten subarrays of an array and collections of key-value pairs within DataWeave objects, arrays, and subarrays. Before you begin, note that 2.x versions of DataWeave are used by Mule 4 apps. For DataWeave in Mule 3 apps, refer to DataWeave version 1.2 examples. For other DataWeave versions, you can use the version selector in the DataWeave table of contents.
Flatten Subarrays with Key-Value Pairs into an Array of Objects
This example shows how flatten
acts on key-value pairs of the input array
defined by the variable arrayOne
. Notice that every key-value pair in the
array becomes a separate DataWeave object.
The example uses this function:
-
flatten
to move the elements from the subarrays to the parent array, eliminate the subarrays, and covert all key-value pairs into a list of objects within the parent array.
[
{
"keyOne": 1
},
{
"keyTwo": 2
},
{
"keyThree": 3
},
{
"keyFour": 4
},
{
"keyFive": 5
},
{
"keySix": 6
}
]
Flatten Combined Arrays
Like the previous DataWeave example, the following returns an array that combines and flattens the
elements from two arrays. This second example applies the selector fruit
to select only the values of the key fruit
and to exclude other values in
the array.
This example uses:
-
++
to combine the objects of two arrays (arrayOne
andarrayTwo
) into a single array. -
flatten
to flatten the combined array into a list of key-value pairs.
%dw 2.0
var arrayOne = [
[
"fruit" : "orange",
"fruit" : "apple"
],
[
"fruit" : "grape",
"notfruit" : "something else"
]
]
var arrayTwo = [
[
{ "fruit" : "kiwi" }
],
"fruit" : "strawberry",
"fruit" : "plum",
{ "fruit" : "banana" },
"notfruit" : "something else"
]
output application/json
---
flatten(arrayOne ++ arrayTwo)
[
{ "fruit": "orange" },
{ "fruit": "apple" },
{ "fruit": "grape" },
{ "notfruit": "something else" },
{ "fruit": "kiwi" },
{ "fruit": "strawberry" },
{ "fruit": "plum" },
{ "fruit": "banana" },
{ "notfruit": "something else" }
]
The only difference between the previous example and the
following example is the addition of the .fruit
selector to the body expression
to select all the fruit
values and to exclude values
of the notfruit
keys from the output array.
%dw 2.0
var arrayOne = [
[
"fruit" : "orange",
"fruit" : "apple"
],
[
"fruit" : "grape",
"notfruit" : "something else"
]
]
var arrayTwo = [
[
{ "fruit" : "kiwi" }
],
"fruit" : "strawberry",
"fruit" : "plum",
{ "fruit" : "banana" },
"notfruit" : "something else"
]
output application/json
---
flatten(arrayOne ++ arrayTwo).fruit
[
"orange",
"apple",
"grape",
"kiwi",
"strawberry",
"plum",
"banana"
]
The next example uses ..*fruit
as a selector in the body expression instead
of .fruit
to return all nested fruit
values in the flattened array. It also
flattens three combined arrays instead of two.
%dw 2.0
var arrayOne = [
[
"fruit" : "orange",
"fruit" : "apple"
],
[
"fruit" : "grape",
"notfruit" : "something else"
]
]
var arrayTwo = [
[
{ "fruit" : "kiwi" }
],
"fruit" : "strawberry",
"fruit" : "plum",
{ "fruit" : "banana" },
"notfruit" : "something else"
]
var arrayThree = [
{ parentOne :
[
{ child :
[
{ grandchild :
{
"fruit" : "watermelon",
"notfruit" : "something else"
}
},
{
fruit : "cantaloupe",
"notfruit" : "something else"
}
]
},
{
fruit : "honeydew",
"notfruit" : "something else"
}
]
},
{ parentTwo:
[
fruit : "cherry",
"notfruit" : "something else"
]
}
]
output application/json
---
flatten(arrayOne ++ arrayTwo ++ arrayThree)..*fruit
[
"orange",
"apple",
"grape",
"kiwi",
"strawberry",
"plum",
"banana",
"watermelon",
"cantaloupe",
"honeydew",
"cherry"
]
Flatten Subarrays into the Parent Array
This example shows how the flatten
function acts on a variety of data types,
including numbers, DataWeave objects, subarrays, a string, a null
value, and
and a key-value pair. Notice that elements of the subarrays become elements of
the parent array, and the subarrays are no longer present.
The example uses this function:
-
flatten
to flatten the subarrays into their parent arrays.
%dw 2.0
var myArray = [
1,
[2,3],
{ a : "b"},
"my string",
[ [4,5], { c : "d"}, 6 ],
null,
"e" : "f"
]
output application/json
---
flatten(myArray)
[
1,
2,
3,
{
"a": "b"
},
"my string",
[
4,
5
],
{
"c": "d"
},
6,
null,
{
"e": "f"
}
]