onKey property

String? onKey
getter/setter pair

In case the flag is placed on a series, on what point key to place it. Line and columns have one key, y. In range or OHLC-type series, however, the flag can optionally be placed on the open, high, low or close key.

API Docs: https://api.highcharts.com/highstock/series.flags.onKey

Implementation

String? onKey;