$distinct

$distinct(array) -> array

Compact type signature<x:x>

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Arrays And Sequences

Source: JSONata

Documentation

Returns an array containing all the values from the array parameter, but with any duplicates removed. Values are tested for deep equality as if by using the equality operator.

Examples

Deduplicate codes

Input

This example uses the diagnoses example input. The expression projects every code value and removes duplicates.

Example input

JSON

[
  {
    "code": "DX-001",
    "display": "tension-type headache",
    "recordedAt": "2026-02-14T09:55:00Z",
    "clinicalStatus": "active",
    "rank": 1
  },
  {
    "code": "DX-014",
    "display": "seasonal allergic rhinitis",
    "recordedAt": "2026-02-14T10:00:00Z",
    "clinicalStatus": "active",
    "rank": 2
  },
  {
    "code": "DX-032",
    "display": "elevated blood pressure reading",
    "recordedAt": "2026-03-01T15:35:00Z",
    "clinicalStatus": "active",
    "rank": 1
  },
  {
    "code": "DX-077",
    "display": "resolved acute sinusitis",
    "recordedAt": "2026-01-05T13:20:00Z",
    "clinicalStatus": "resolved",
    "rank": 3
  }
]

Expression

$distinct(code)

Result

["DX-001", "DX-014", "DX-032", "DX-077"]