const retrievedFeatureTypes = await client.geospatial.featureType.retrieve([ { externalId: 'ocean_temperature' } ]);

{
  "items": [
    {
      "externalId": "ocean_temperature",
      "dataSetId": 1278028,
      "createdTime": 1629784673505,
      "lastUpdatedTime": 1629784673505,
      "properties": {
        "temperature": {
          "type": "DOUBLE"
        },
        "location": {
          "type": "POINT",
          "srid": 4326
        },
        "createdTime": {
          "type": "LONG"
        },
        "lastUpdatedTime": {
          "type": "LONG"
        },
        "externalId": {
          "type": "STRING",
          "size": 32
        }
      },
      "searchSpec": {
        "location_idx": {
          "properties": [
            "location"
          ]
        },
        "createdTimeIdx": {
          "properties": [
            "createdTime"
          ]
        },
        "lastUpdatedTimeIdx": {
          "properties": [
            "lastUpdatedTime"
          ]
        },
        "externalIdIdx": {
          "properties": [
            "externalId"
          ]
        }
      }
    }
  ]
}