Identifier Transform

The identifier transform extends data objects with a globally unique key value. Identifier values are assigned using an internal counter. This counter is shared across all instances of this transform within a single Vega view, including different data sources. Note, however, that the counter is not shared across different Vega views.

Transform Parameters

Property Type Description
as String Required. The output field at which to write the unique identifier value.


Given this data:

  {"foo": "a"},
  {"foo": "b"}

This example writes unique identifier values to the id field of each newly seen data object.

{"type": "identifier", "as": "id"}


```json [ {“foo”: “a”, “id”: 1}, {“foo”: “b”, “id”: 2} ]