Descendants Selector (..myKey)
The .. selector acts on arrays and objects.
This selector applies to the context using the form ..myKey, and it retrieves the values of all matching key-value pairs in the sub-tree under the selected context. Regardless of the hierarchical structure of the fields, the output is returned at the same level.
In this example, all of the fields that match the key name are placed in a list called names regardless of their cardinality in the tree of the input data.
The descendants selector (..) is the perfect tool to use when you need the values for a certain key no matter where they appear in a piece of data. Here’s an example:
{
“echo”: {“value”: “Hello there!”},
“sequence”: [
{
“echo”: “Getting details…”,
“try”: {
“curl”: “somelocation.com”,
“echo”: “Success!”
}
},
{
“grep”: “Success”
}
]
}
%dw 2.0
output json
—
payload..echo
[{ “value”: “Hello there!”}, “Getting details…”, “Success!”]
This selector can be combined with the multi value selector to also find repeated keys.
DataWeave Script:
%dw 2.0
output application/json
—
{ names: payload.people..name }
Input JSON Payload:
{
“people”: {
“person”: {
“name”: “Nial”,
“address”: {
“street”: {
“name”: “Italia”,
“number”: 2164
},
“area”: {
“zone”: “San Isidro”,
“name”: “Martinez”
}
}
}
}
}
Output JSON:
{
“names”: [
“Nial”,
“Italia”,
“Martinez”
]
}
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