field<T> method
Reads field name, coerced to T.
A nullable T makes the field optional.
Implementation
Result<T, Rejection> field<T>(String name) {
final raw = fields[name];
if (raw == null) {
if (null is T) return Ok(null as T);
return Err(Rejection.badRequest('form field "$name" is required'));
}
return coerce<T>(raw, source: 'form field "$name"');
}