Function getConditionalIcon

getConditionalIcon(set: IconSet, index: number): ConditionalIconSpec | null
Returns the icon a band of a built-in set draws, or null if the band is out of range.
Parameters
- set: IconSet
  The set to read.
- index: number
  The band, 0 being the lowest.
Returns ConditionalIconSpec | null

Remarks
set is asked per cell rather than per rule because a rule may borrow each band's icon from a different set — see IConditionalFormat.IconSetDecoration.