supertypes 0.0.2

A library for better, super records

Supertypes is a library for generating complex records. This library has been heavily inspired by TypeScript's Utility Types.

Installation

Add supertypes and it's companion generator to your pubspec.yaml. The easiest way to do this is to use the command line:

For Dart projects:

dart pub add supertypes dev:supertypes_generator dev:build_runner

For Flutter projects:

flutter pub add supertypes dev:supertypes_generator dev:build_runner

To generate the types, run build_runner:

For Dart projects:

dart run build_runner build # Build once
dart run build_runner watch # Build continuously

For Flutter projects:

flutter pub run build_runner build # Build once
flutter pub run build_runner watch # Build continuously

Usage

Every file containing a supertype must have the following:

It should start with a part directive.

import 'package:supertypes/supertypes.dart';

part 'example.supertypes.dart';

It should contain a typedef with the name of the supertype, prefixed with $ for public generated records, or _$ for private generated records.

// Generates a public record called `Example`
@superType
typedef $Example = ();

// Generates a private record called `_Example`
@superType
typedef _$Example = ();

Index

• Modifier types
  • Partial
  • Required

Modifier types

Modifier types are types that take one or more types and return a new type.

Partial

The Partial modifier type takes a type and makes all of it's fields optional.

import 'package:supertypes/supertypes.dart';

part 'person.supertypes.dart';

typedef Person = ({
String firstName,
String lastName,
int age,
});

// We want to make all the field nullable to support partial updates
@superType
typedef $UpdatePerson = Partial<Person>;

// This generates:
typedef UpdatePerson = ({
String? firstName,
String? lastName,
int? age,
});

Required

The Required modifier type takes a type and makes all of it's fields required.

import 'package:supertypes/supertypes.dart';

part 'person.supertypes.dart';

// Let's say we have a person type with `lastName` nullable, 
// and we can't update the type easily. 
// We can instead create a new type with all fields required.
typedef Person = ({
String firstName,
String? lastName,
int age,
});

// We want to make all the field nullable to support partial updates
@superType
typedef $CreatePerson = Required<Person>;

// This generates:
typedef CreatePerson = ({
String firstName,
String lastName,
int age,
});

Future features:

• More modifier types
  • Omit - Omit fields from a type
  • Pick - Pick fields from a type
  • Awaited - Unwrap a Future type recursively
  • WithRequired - Make certain fields required
  • WithPartial - Make certain fields optional
  • Intersect - Intersect two types
• JSON serialization and deserialization for records
  • Generate fromJson top level function
  • Generate toJson extension method on the record
• Support for using classes in the supertype records by extracting their fields