prefer_enums_by_name

v0.4.0 Warning Fix Collection & Type

Using .firstWhere((e) => e.name == value) on enum values can be replaced with the built-in .byName() method, available since Dart 2.15. The dedicated method is more concise, more readable, and throws a clear ArgumentError when the name is not found.

Why use this rule

.byName() was specifically designed for looking up enum values by their string name. It is shorter, self-documenting, and provides a better error message on failure compared to the firstWhere approach which throws a generic StateError.

See also: Dart enums

Don’t

enum Style { bold, italic, underline }

void example() {
  // Use .byName() instead of .firstWhere()
  final style = Style.values.firstWhere(
    (def) => def.name == 'bold',
  );

  // Reversed comparison also detected
  final style2 = Style.values.firstWhere(
    (def) => 'italic' == def.name,
  );

  // Variable comparison
  final name = 'underline';
  final style3 = Style.values.firstWhere((def) => def.name == name);
}

Do

enum Style { bold, italic, underline }

void example() {
  final style = Style.values.byName('bold');

  final name = 'underline';
  final style2 = Style.values.byName(name);
}

Configuration

To disable this rule:

plugins:
  many_lints:
    diagnostics:
      prefer_enums_by_name: false