refusalOf method

String? refusalOf(Object? value)

Why value is not the shape this field takes, or null when it is.

Null is always taken: an absent field is what every optional field means by "not set". A number outside min and max is taken too; see isInside.

Implementation

String? refusalOf(Object? value) {
  if (value == null) return null;
  bool numbers(int count) =>
      value is List &&
      value.length == count &&
      value.every((Object? e) => e is num && e.isFinite);
  final fits = switch (kind) {
    FieldKind.number => value is num && value.isFinite,
    FieldKind.integer => value is int || (value is num && value % 1 == 0),
    FieldKind.toggle => value is bool,
    FieldKind.choice => value is String && choices.contains(value),
    FieldKind.color => numbers(3) || numbers(4),
    FieldKind.vector3 => numbers(3),
    FieldKind.text || FieldKind.entity => value is String,
    FieldKind.asset =>
      value is String &&
          (suffixes.isEmpty ||
              suffixes.any(
                (String s) => value.toLowerCase().endsWith(s.toLowerCase()),
              )),
    // A kind this build does not know takes what a document can hold.
    _ => true,
  };
  if (fits) return null;
  return switch (kind) {
    FieldKind.choice => '"$key" is one of ${choices.join(', ')}, not $value',
    FieldKind.color =>
      '"$key" is a colour, three or four numbers, not $value',
    FieldKind.vector3 => '"$key" is three numbers, not $value',
    FieldKind.asset when suffixes.isNotEmpty =>
      '"$key" is a path ending in ${suffixes.join(' or ')}, not $value',
    _ => '"$key" is ${_article(kind.name)}, not $value',
  };
}