schemantic 0.0.1-dev.6

A general-purpose builder for generating type-safe data classes and JSON schemas from abstract definitions.

example/schemantic_example.dart

// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import 'package:schemantic/schemantic.dart';

part 'schemantic_example.schema.g.dart';

@Schematic()
abstract class AddressSchema {
  String get street;
  String get city;
  String get zipCode;
}

/// Define a schema using the @Schematic annotation.
/// This will generate a concrete [User] class and a [UserType] utility.
@Schematic()
abstract class UserSchema {
  @StringField(minLength: 2, maxLength: 50, pattern: r'^[a-zA-Z\s]+$')
  String get name;
  @IntegerField(
    name: 'years_old',
    description: 'Age of the user',
    minimum: 0,
    maximum: 120,
  )
  int? get age;
  @Field(description: 'Is this user an admin?')
  bool get isAdmin;

  // Nested schema
  AddressSchema? get address;
}

void main() async {
  // 1. Create an instance using the generated class
  final address = Address.from(
    street: '123 Main St',
    city: 'Springfield',
    zipCode: '62704',
  );

  final user = User.from(
    name: 'Alice',
    age: 30,
    isAdmin: true,
    address: address,
  );

  print('--- Instance ---');
  print('Name: ${user.name}');
  print('Age: ${user.age}');
  print('Is Admin: ${user.isAdmin}');
  print('Address: ${user.address?.street}, ${user.address?.city}');

  // 2. Serialize to JSON
  final json = user.toJson();
  print('\n--- JSON Serialization ---');
  print(json);
  // Output: {name: Alice, age: 30, isAdmin: true, address: {street: 123 Main St, city: Springfield, zipCode: 62704}}

  // 3. Parse from JSON
  final parsed = UserType.parse({
    'name': 'Bob',
    'isAdmin': false,
    'address': {
      'street': '456 Elm St',
      'city': 'Shelbyville',
      'zipCode': '62705',
    },
  });
  print('\n--- JSON Parsing ---');
  print('Parsed Name: ${parsed.name}'); // Bob
  print('Parsed City: ${parsed.address?.city}'); // Shelbyville

  // 4. Access JSON Schema at runtime
  final schema = UserType.jsonSchema();
  print('\n--- JSON Schema ---');
  print(schema.toJson());

  // 5. Validation
  print('\n--- Validation ---');

  // Valid data
  // Valid data
  final validData = <String, dynamic>{
    'name': 'Charlie',
    'isAdmin': true,
    'address': <String, dynamic>{
      'street': '789 Oak St',
      'city': 'Capital City',
      'zipCode': '62706',
    },
  };
  final validResult = await schema.validate(validData);
  if (validResult.isEmpty) {
    print('✅ Data is valid.');
  } else {
    print('❌ Validation failed: $validResult');
  }

  // Invalid data (missing required field 'isAdmin' and invalid nested field)
  final invalidData = <String, dynamic>{
    'name': 'Dave',
    'address': <String, dynamic>{
      // Missing required street, city, zipCode
    },
  };
  final invalidResult = await schema.validate(invalidData);
  if (invalidResult.isNotEmpty) {
    print('✅ Correctly detected invalid data:');
    for (final error in invalidResult) {
      print('  - $error');
    }
  }

  // 6. Dynamic Types (listType & mapType)
  print('\n--- Dynamic Types ---');

  // List of Strings
  final stringList = listType(UserType);
  final parsedList = stringList.parse([
    {'name': 'Alice', 'isAdmin': true},
    {'name': 'Bob', 'isAdmin': false},
  ]);
  print(
    'Parsed List: $parsedList',
  ); // [{name: Alice, isAdmin: true}, {name: Bob, isAdmin: false}]
  print('List Schema: ${stringList.jsonSchema().toJson()}');

  // Map of String -> User
  final scores = mapType(StringType, UserType);
  final parsedScores = scores.parse({
    'Alice': {'name': 'Alice', 'isAdmin': true},
    'Bob': {'name': 'Bob', 'isAdmin': false},
  });
  print(
    'Parsed Map: $parsedScores',
  ); // {Alice: {name: Alice, isAdmin: true}, Bob: {name: Bob, isAdmin: false}}
  print('Map Schema: ${scores.jsonSchema().toJson()}');
}