luthor_generator 1.0.0

Generate luthor schemas

example/example.md

luthor_generator example

Add luthor as a dependency, and luthor_generator and build_runner as dev dependencies. This example also uses json_serializable, which is optional: a hand-written fromJson works too.

dart pub add luthor json_annotation dev:luthor_generator dev:build_runner dev:json_serializable

Annotate a model with @luthor. Put validation annotations on the constructor parameters or on the fields. The class needs a fromJson factory, and validateSelf() is generated only when it also has a toJson method:

// lib/user.dart
import 'package:json_annotation/json_annotation.dart';
import 'package:luthor/luthor.dart';

part 'user.g.dart';

enum Role { admin, member }

@luthor
@JsonSerializable()
class User {
  const User({
    @HasMin(2) required this.name,
    @IsEmail() required this.email,
    @HasMin(0) this.age,
    this.role = Role.member,
  });

  final String name;
  final String email;
  final int? age;
  final Role role;

  factory User.fromJson(Map<String, dynamic> json) => _$UserFromJson(json);

  Map<String, dynamic> toJson() => _$UserToJson(this);
}

Generate the code:

dart run build_runner build

This adds $UserSchema, $UserValidate, UserSchemaKeys, UserErrorKeys and a validateSelf() extension to user.g.dart:

final SchemaValidator $UserSchema = l.schema({
  UserSchemaKeys.name: l.string().min(2).required(),
  UserSchemaKeys.email: l.string().email().required(),
  UserSchemaKeys.age: l.int().min(0),
  UserSchemaKeys.role: l.oneOf(["admin", "member"]),
}).withName("User");

ValidationResult<User> $UserValidate(Object? json) =>
    $UserSchema.validateSchema(json, fromJson: User.fromJson);

Validate JSON with $UserValidate, and an existing instance with validateSelf():

import 'package:luthor/luthor.dart';

import 'user.dart';

void main() {
  final result = $UserValidate({'name': 'A', 'email': 'not-an-email'});

  switch (result) {
    case ValidationSuccess(data: final user):
      print('Valid: ${user.name}');
    case ValidationFailure(:final errors):
      print(errors);
      print(result.getError(UserErrorKeys.email));
  }

  const user = User(name: 'Ada', email: '[e-mail]');
  print(user.validateSelf().isValid); // true
}

The generator also works with freezed and dart_mappable classes. See examples/luthor_generator in the repository for runnable examples, and the documentation for every annotation.