TextRange constructor
Creates a text range.
The start
and end
arguments must not be null. Both the start
and
end
must either be greater than or equal to zero or both exactly -1.
Instead of creating an empty text range, consider using the empty constant.
Implementation
const TextRange({
@required this.start,
@required this.end
}) : assert(start != null && start >= -1),
assert(end != null && end >= -1);