const datapoints = await client.datapoints.retrieveLatest([
  {
   before: 'now',
   id: 123
 },
 {
   externalId: 'abc',
   before: new Date('21 jan 2018'),
 }
]);

{
  "items": [
    {
      "id": 4503599627370496,
      "isString": true,
      "type": "<string>",
      "datapoints": [
        {
          "timestamp": 1638795554528,
          "value": 123,
          "status": {
            "code": 123,
            "symbol": "<string>"
          }
        }
      ],
      "externalId": "<string>",
      "instanceId": {
        "space": "<string>",
        "externalId": "<string>"
      },
      "isStep": true,
      "unit": "<string>",
      "unitExternalId": "<string>",
      "nextCursor": "<string>"
    }
  ]
}