avoid-local-functions

added in: 1.10.0

Pro+

Warns when a function declaration is a local function.

Local functions complicate the readability of the containing function by inverting its flow (you see a lot of code at first that will be somehow used later) and can lead to unexpected inclusion of outer scope variables.

Example

❌ Bad:

bool someFunction(String externalValue) {
  final value = 'some value';

  // LINT: Avoid local functions. Try converting this function to a method or a top-level function instead.
  bool isValid() {
    // some
    // additional
    // logic
  }

  return isValid() && externalValue != value;
}

✅ Good:

bool someFunction(String externalValue) {
  final value = 'some value';

  return isValid() && externalValue != value;
}

// Correct, moved outside of 'someFunction'
bool isValid() {
  // some
  // additional
  // logic
}

Example​

Example