isEmpty property
bool isEmptyReturns true if there are no elements in this collection.
May be computed by checking if iterator.moveNext() returns false.
Source
bool get isEmpty => !iterator.moveNext();
    © 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
    https://api.dartlang.org/stable/1.24.3/dart-core/Iterable/isEmpty.html