transformStack method
Implementation
void transformStack(List<Delta> stack, Delta delta) {
for (var i = stack.length - 1; i >= 0; i -= 1) {
final oldDelta = stack[i];
stack[i] = delta.transform(oldDelta, true);
delta = oldDelta.transform(delta, false);
if (stack[i].length == 0) {
stack.removeAt(i);
}
}
}