minLength function
Creates a validator that fails when a string value has fewer than n characters.
Returns message (or 'Must be at least $n characters.' by default) when invalid,
and null when valid.
final passwordField = BloomFormField(
validators: [minLength(8, 'Password must be at least 8 characters.')],
);
Implementation
String? Function(String) minLength(int n, [String? message]) =>
(v) => v.length < n ? (message ?? 'Must be at least $n characters.') : null;