no_default_cases

No default cases.

This rule is currently experimental and available as of Dart 2.9.

Switches on enums and enum-like classes should not use a default clause.

Enum-like classes are defined as concrete (non-abstract) classes that have:

• only private non-factory constructors
• two or more static const fields whose type is the enclosing class and
• no subclasses of the class in the defining library

DO define default behavior outside switch statements.

BAD:

  switch (testEnum) {
    case TestEnum.A:
      return '123';
    case TestEnum.B:
      return 'abc';
    default:
      return null;
  }

GOOD:

  switch (testEnum) {
    case TestEnum.A:
      return '123';
    case TestEnum.B:
      return 'abc';
  }
  // Default here.
  return null;

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

linter:
  rules:
    - no_default_cases

Unless stated otherwise, the documentation on this site reflects Dart 3.5.4. Page last updated on 2024-07-03. View source or report an issue.