Function required

packages/forms/signals/src/api/rules/validation/required.ts:33–53

(
  path: SchemaPath<TValue, SchemaPathRules.Supported, TPathKind>,
  config?: BaseValidatorConfig<TValue, TPathKind> & {
    when?: NoInfer<LogicFn<TValue, boolean, TPathKind>>;
  },
)

 * @publicApi 22.0
 */
export function required<TValue, TPathKind extends PathKind = PathKind.Root>(
  path: SchemaPath<TValue, SchemaPathRules.Supported, TPathKind>,
  config?: BaseValidatorConfig<TValue, TPathKind> & {
    when?: NoInfer<LogicFn<TValue, boolean, TPathKind>>;
  },
): void {
  const REQUIRED_MEMO = metadata(path, createMetadataKey<boolean>(), (ctx) =>
    config?.when ? config.when(ctx) : true,
  );
  metadata(path, REQUIRED, ({state}) => state.metadata(REQUIRED_MEMO)!()!);
  validate(path, (ctx) => {
    if (ctx.state.metadata(REQUIRED_MEMO)!() && isEmpty(ctx.value())) {
      if (config?.error) {
        return getOption(config.error, ctx);
      } else {
        return requiredError({message: getOption(config?.message, ctx)});
      }
    }
    return undefined;
  });
}