json_model_builder

Description:

json model builder

Build JSON serializable classes without code gen or mirrors #
This library provides a way to create modeles easily usable from code that can be serialized into/from JSON.
Instead of directly using variables of the corresponding types we use 'JsonType'.
A 'JsonType' can convert a given type from and to json.
Models #
Models are custom JsonTypes with custom entries and types.
A model can

Be serialized to JSON
Be instanciated from parsed JSON
Have entries with a type of Model
Be able to correctly create it sub model entries from JSON

If you have a Model that has some entry with type of other model, this will work fine.
Instanciating the parent from json will also instanciate the child correctly.
Example #

class SocialNetwork extends ModelBuilder {
@override
Iterable<JsonType> get values => [users, posts, likes];

JsonList<User> get users => jsonList<User>('users', User.new);

JsonList<Post> get posts => jsonList<Post>('posts', () => Post({}));

JsonMap<JsonInt> get likes => jsonMap<JsonInt>('likes_by_post_id', JsonInt.new);

JsonMap<JsonList<Post>> get collections => jsonMap('collections', () => JsonList(() => Post({})));
}

class Post extends ModelBuilder {
// Add this lines to instanciate from json source directly
Post(super.source);

@override
Iterable<JsonType> get values => [id, title, content, creator];

// Functions passed as default value are called when instanciating the model
JsonInt get id => jsonInt('id', nextId);

JsonString get title => jsonString('title');

JsonString get content => jsonString('content');

JsonString get creator => jsonString('creator_email');
}

class User extends ModelBuilder {
@override
Iterable<JsonType> get values => [name, email, birthday, address];

JsonString get name => jsonString('name');

JsonString get email => jsonString('email');

JsonDateTime get birthday => jsonDateTime('birthday');

Address get address => jsonModel<Address>('address', Address.new);
}

class Address extends ModelBuilderNullable {
@override
Iterable<JsonType> get values => [street, number, street, city, state, country];

JsonString get street => jsonString('street');

JsonIntNullable get number => jsonIntNullable('number');

JsonString get zip => jsonString('zip_code');

JsonStringNullable get city => jsonStringNullable('city');

JsonString get state => jsonString('state');

JsonString get country => jsonString('country');
}

void main(List<String> args) {
final faceGram = SocialNetwork();

final user = User();
user.setFromJson({
'name': 'Tomás',
'email': '[email protected]',
'birthday': '2020-04-05T00:00:00.000',
'address': {
'street': 'Some Street',
'number': 123,
'zip_code': '1000',
'city': 'Some City',
'state': 'Some State',
'country': 'United Land'
}
});

faceGram.users.add(user);

assert(faceGram.users[0] == user);
assert(!user.address.isNull);
assert(user.address.state.value == 'Some State');

faceGram.posts.add(Post({'title': 'Dart is awesome', 'content': 'Lorem ipsum ...', 'creator_email': user.email}));
final post = faceGram.posts[0];
assert(post.creator.value == '[email protected]');

final y2020 = Post({
'title': JsonString()..setFromJson(2020),
'content': JsonString()..set('Year 2020, ...'),
});

y2020.creator.set(user.email.value);
y2020.title.value += ', the pandemic';

faceGram.posts.add(y2020);
assert(faceGram.posts[1].title.value == '2020, the pandemic');

faceGram.collections['code'] = JsonList<Post>(() => Post({}));

faceGram.collections['code']!.add(Post({'title': 'I HATE SOFTWARE'}));
faceGram.collections['code']!.add(Post({'title': 'I LOVE SOFTWARE'}));

faceGram.collections['history'] = JsonList<Post>(() => Post({}));

faceGram.collections['history']!.add(Post({'title': 'Year 2020 pandemic'}));
}

int id = 0;

int nextId() => id++;

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