List<E>.generate constructor Null safety
Generates a list of values.
Creates a list with length positions and fills it with values created by
calling generator for each index in the range 0 .. length - 1
in increasing order.
List<int>.generate(3, (int index) => index * index); // [0, 1, 4]
The created list is fixed-length if growable is set to false.
The length must be non-negative.
Implementation
external factory List.generate(int length, E generator(int index),
{bool growable = true});