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$selectKeys

$selectKeys(object?, keysToSelect?) -> object
Compact type signature<o-a<s>?:o>

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

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Objects And Structure

Source: FUME

Documentation​

Returns a new object containing only the named keys.

keysToSelect can be a single string or an array of strings, and each selector is compared to object keys using string conversion. If keysToSelect is undefined or null, the function returns an empty object.

Examples​

Select only specific keys​

Input

This example uses the patient-summary example input. The expression selects only the referenced top-level 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

$selectKeys($, ["patientId", "birthDate"])

Result

{
  "patientId": "pat-0001",
  "birthDate": "1990-06-12"
}