Skip to main content

prefer-switch-with-enums

added in: 1.12.0
style
⚙️
Pro+
preset: recommended

Suggests to use a switch statement or expression instead of conditionals with multiple enum values.

When it comes to enum values, the analyzer warns you when a new enum value is not covered by a switch case. This feature is not available for if statements and conditional expressions. Therefore using switches where possible can reduce the number of potential bugs.

⚙️ Config​

Set ignore-contains (default is false) to exclude .contains() (example).

analysis_options.yaml
dart_code_metrics:
  rules:
    - prefer-switch-with-enums:
        ignore-contains: false

Example​

❌ Bad:

void fn(MyEnum value) {
  // LINT: Prefer switch statement/expression when checking enum values.
  if (value == MyEnum.first) {
    print(value);
  } else if (value == MyEnum.second) {
    print(value);
  } else if (value == MyEnum.third) {
    print(value);
  }

  // LINT: Prefer switch statement/expression when checking enum values.
  if (value == MyEnum.first || value == MyEnum.second) {
  } else {}

  final possibleValues = {MyEnum.first, MyEnum.second};
  // LINT: Prefer switch statement/expression when checking enum values.
  if (possibleValues.contains(value)) {}
}

enum MyEnum {
  first,
  second,
  third,
}

✅ Good:

void fn(MyEnum value) {
  switch (value) {
    case MyEnum.first:
      ...
    
    case MyEnum.second:
      ...

    case MyEnum.third:
      ...
  }
}

Example with "ignore-contains"​

Config
analysis_options.yaml
dart_code_metrics:
  rules:
    - prefer-switch-with-enums:
        ignore-contains: true

✅ Good:

void fn(MyEnum value) {
  final possibleValues = {MyEnum.first, MyEnum.second};
  if (possibleValues.contains(value)) {} // Correct, ignored
}