none method

bool none(ElementPredicate<T> predicate)

Returns true if no element satisfies predicate.

Equivalent to !any(predicate), but reads as intent at the call site and avoids the easy-to-misplace ! that flips the meaning silently. Short-circuits on the first match, so it is cheap on long iterables.

An empty iterable returns true (vacuously: nothing violates the predicate), matching the convention of Iterable.every.

Example:

[1, 3, 5].none((n) => n.isEven); // true
[1, 2, 3].none((n) => n.isEven); // false
<int>[].none((n) => n.isEven);   // true

Audited: 2026-06-12 11:26 EDT

Implementation

bool none(ElementPredicate<T> predicate) {
  for (final T element in this) {
    if (predicate(element)) {
      return false;
    }
  }
  return true;
}