Validation

❗️ Important: Never throw inside a .refine() function — ZodArt will not catch it.

In addition to built-in validation methods like .min(), you can add your own validation logic using the .refine() method.

The .refine() method should return true if the value is valid, or false otherwise. When .refine() returns false, ZodArt creates a ZIssueCustom issue. You can optionally provide a message or code to include it in the issue.

See full example.

ℹ️ To return multiple issues or apply advanced validations use the .superRefine() method.

import 'package:zodart/zodart.dart';

part 'refine_method.zodart.dart';
part 'refine_method.zodart.type.dart';

/// Schema defined using ZodArt
@ZodArt.generateNewClass(outputClassName: 'Person')
abstract class PersonSchema {
  /// Validates that:
  /// - `firstName` is from 1 to 20 characters long
  /// - `lastName` is from 1 to 30 characters long
  /// - `validFrom` is a timestamp in seconds
  /// - `validTo` is an optional timestamp in seconds
  static final schema = (
    firstName: ZString().min(1).max(20),
    lastName: ZString().min(1).max(30),
    validFrom: ZInt(),
    validTo: ZInt().optional(),
  );

  // Access to generated helper methods like props list etc.
  static const z = _PersonSchemaUtils();
  static final ZObject<Person> zObject = z.zObject;
}

void main() {
  // Refine the `personSchema` to ensure that `validFrom` < `validTo`
  final refinedPersonSchema = PersonSchema.zObject.refine(
    (person) {
      final validTo = person.validTo;
      return validTo == null || person.validFrom < validTo;
    },
    message: 'validFrom must be earlier than validTo.',
  );

  // Parse raw input (e.g. from an API, user form, etc.)
  // ZodArt infers the type of `result.value` as `Person`
  final result = refinedPersonSchema.parse({
    'firstName': 'Zod',
    'lastName': 'Art',
    'validFrom': 1749952242,
    'validTo': 631152000,
  });

  // Prints the custom error message 'validFrom must be earlier than validTo.'
  print(result.issueSummary);
}