prefer-extracting-function-callbacks

added in: 1.19.0

style

⚙️

Pro+

Warns when an inline callback is passed as an argument to a function or method invocation.

note

For this rule it's recommended to exclude the test folder.

⚙️ Config

Set allowed-line-count (default is none) to configure the maximum number of lines after which the rule should trigger.

Set ignored-named-arguments (default is empty) to ignore specific named parameters.

Set ignored-invocations (default is empty) to ignore function callbacks in specific invocations.

dart_code_metrics:
  ...
  rules:
    ...
    - prefer-extracting-function-callbacks:
        ignored-named-arguments:
          - onPressed
        allowed-line-count: 3

Example

❌ Bad:

void fn() {
  // LINT
  listen(onPressed: () { 
    // Some
    // Huge
    // Callback
  });
}

void listen({
  void Function()? onPressed,
}) {}

✅ Good:

void fn() {
  listen(onPressed: handlePressed);
}

void handlePressed() { 
  // Some
  // Huge
  // Callback
}

void listen({
  void Function()? onPressed,
}) {}