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

Usage

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"}

Results:

[
  {"foo": "a", "id": 1},
  {"foo": "b", "id": 2}
]