prefer_is_not_empty

Use isNotEmpty for Iterables and Maps.

PREFER x.isNotEmpty to !x.isEmpty for Iterable and Map instances.

When testing whether an iterable or map is empty, prefer isNotEmpty over !isEmpty to improve code readability.

BAD:

if (!sources.isEmpty) {
  process(sources);
}

GOOD:

if (todo.isNotEmpty) {
  sendResults(request, todo.isEmpty);
}

To enable the prefer_is_not_empty rule, add prefer_is_not_empty under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - prefer_is_not_empty

If you're instead using the YAML map syntax to configure linter rules, add prefer_is_not_empty: true under linter > rules:

linter:
  rules:
    prefer_is_not_empty: true