prefer-primary-constructors

v1.40.0

style

effort: 4m

dart 3.13+

configurable

has IDE fix

has auto-fix

pro+

Suggests converting simple classes (with only fields) to primary constructors.

⚙️ Config

Set allow-getters (default is false) to also highlight classes with getters.

analysis_options.yaml

dcm:
  rules:
    - prefer-primary-constructors:
        allow-getters: false

Example

❌ Bad:

class MyClass {
  final String value;
  final int another;

  // LINT: Prefer primary constructors for simple classes.
  const new(this.another, this.value);
}

class WithStaticField {
  static const _field = 'value';

  final String value;
  final int another;

  // LINT: Prefer primary constructors for simple classes.
  const new(this.another, this.value);
}

✅ Good:

class Some {
  String? value;
  int? another;
}

class Another {
  final String value;
  final int another;

  const new(this.another, this.value);

  new named(this.another, this.value);
}

class WithMethods {
  final String value;
  final int another;

  const new(this.another, this.value);

  void work() {}
}