nd_core_utils is a small utility library for dart core.
var iteratable = NDClosureIterable(get: () => MyIterator());
var iterator = NDClosureIterator(
current: () {
// return current
},
moveNext() {
// move next
// return result
}
);
final Iteratable it = <int?>[1, null, 2];
print(it.notNull());
// [1, 2]
final Iteratable it = [1, 2, 3];
print(it.insertSeparator(100));
// [1, 100, 2, 100, 3]
final List list = <int?>[1, null, 3];
print(list.notNullInsertSeparator(100));
// [1, 100, 3]