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$keys

$keys(value?) -> array
Compact type signature<x-:a<s>>

If value is omitted, the current context value is used.

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Objects And Structure

Source: JSONata

Documentation​

Returns an array containing the keys in the object. If the argument is an array of objects, then the array returned contains a de-duplicated list of all the keys in all of the objects.

Examples​

List keys on an object​

Input

This example uses the patient-summary example input. The expression selects the nested identifiers object and lists its keys.

Example input

JSON
{
  "patientId": "pat-0001",
  "name": {
    "given": "Avery",
    "family": "Reed",
    "display": "Avery Reed"
  },
  "birthDate": "1990-06-12",
  "sex": "female",
  "primaryCareTeam": {
    "organization": "ExampleCare",
    "facility": "ExampleCare Clinic",
    "practitioner": {
      "practitionerId": "prac-4001",
      "display": "Jordan Kim"
    }
  },
  "identifiers": {
    "memberId": "mbr-3001",
    "recordNumber": "rec-5001"
  },
  "tags": [
    "demo",
    "fictional"
  ],
  "_xmlTagName": "patientSummary"
}

Expression

$keys(identifiers)

Result

["memberId", "recordNumber"]