Lets make enums 🚀 by adding some useful extension methods.
Say good bye to switch-case and if-else blocks.
Inspired by freezed
Features
-
Generate Some Useful Methods
- when
- mayBeWhen
- onlyWhen
- map
- mapSimply
- mayBeMap
-
Generate Value Checking Getters
-
Generate Custom Extension Value
-
Title case of enum name
Getting started
Add following dependencies -
dependencies:
yaml: ^3.1.0
enum_ext: ^1.0.0
dev_dependencies:
build_runner:
enum_ext_gen: ^1.0.0
Usage
Add the part directive in the file
part 'file_name.g.dart';
Extension methods
In order to generate extension methods, simply annotate the enum with @EnumExt()
@EnumExt()
enum HttpResponse { ok, notFound, internalServerError }
⚙️ Now generate the code using build_runner.
Dart only -
dart pub run build_runner build
// OR
dart pub run build_runner watch
Flutter -
flutter pub run build_runner build
// OR
flutter pub run build_runner watch
This will generate all these extension methods for you
final response = HttpResponse.internalServerError;
response.when(
ok: (e) {
// Do some actions only if the response is HttpResponse.ok
},
notFound: (e) {
// Do some actions only if the response is HttpResponse.notFound
},
internalServerError: (e) {
// Do some actions only if the response is HttpResponse.internalServerError
},
);
response.mayBeWhen(
ok: (e) {
// Do some actions only if the response is HttpResponse.ok
},
orElse: (e) {
// Do some actions only if the response is something other than HttpResponse.ok
},
);
response.onlyWhen(
ok: (e) {
// Do some actions only if the response is HttpResponse.ok
},
);
final value = response.map(
ok: (e) => "Some value based on HttpResponse.ok",
notFound: (e) => "Some value based on HttpResponse.notFound",
internalServerError: (e) => "Some value based on HttpResponse.internalServerError",
);
final something = response.mapSimply(
ok: "Some value based on HttpResponse.ok",
notFound: "Some value based on HttpResponse.notFound",
internalServerError: "Some value based on HttpResponse.internalServerError",
);
Note :- when(),
onlyWhen(),mayBeWhen()methods used when do just want to perform some task based on specific enum properties, whereas map(),mayBeMap(),mapSimply()methods are used to return a value based on the enum.
Value Checking Getters
It will also generate value checking getter like
response.isOk // response == Response.ok
response.isNotOk // response != Response.ok
If you do not want to generate value checking getters, you can set conditionalGetters: false like this
EnumExt(conditionalGetters: false)
Extension value
In order to generate extension value, annotate enum properties with @EnumExtValue(...)
⚠️Note:- Any enum propery that is not annotated with @EnumExtValue(...) will simply return null
⚠️Note:- Supported values for @EnumExtValue(...) are String, int, double, List, Map, Set and Symbol. Any other vaue will be replaced by null
Lets add some extension values to the HttpResponse enum
@EnumExt()
enum HttpResponse {
@EnumExtValue(200)
ok,
@EnumExtValue(404)
notFound,
@EnumExtValue(500)
internalServerError,
}
This will generate a getter extension named extValue on the enum.
final response = HttpResponse.internalServerError;
print(response); // HttpResponse.internalServerError
print(response.index); // 2
print(response.name); // internalServerError
print(response.extValue); // 500 <-- 🔥 Extension
and
HttpResponse.values.byExtValue(500);// returns HttpResponse.internalServerError
Title case of enum name
It also generate title getter extension in order to get Title Case of enum property name.
@EnumExt()
enum HttpResponse { ok, notFound, internalServerError }
void main() {
final response = HttpResponse.internalServerError;
print(response.title); // Internal Server Error
}