keys property
The keys accessor;
final stack = Stack(…)..keys = (thisArg, data, [args]) => ["apples", "bananas", "cherries", "durians"];
stack.keys; // (thisArg, data, [args]) => ["apples", "bananas", "cherries", "durians"]
The keys accessor defaults to the empty list. A series (layer) is generated (see Stack.call) for each key. Keys are typically strings, but they may be arbitrary values. The series’ key is passed to the value accessor, along with each data point, to compute the point’s value.
Implementation
List<K> Function(Stack<K, T>, Iterable<T>, [List<Object?>?]) keys =
constant([]);