prefer_is_not_empty

Use isNotEmpty for Iterables and Maps.

This rule is available as of Dart 2.0.0.

Rule sets: core, recommended, flutter

This rule has a quick fix available.

Details

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);
}

Usage

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