[go_router_builder] Support extension types as route arguments #170870
Description
Use case
Using Extension types to create type-safe IDs is a common practice (e.g., extension type const ArticleId(String value) {}).
However, when this extension type is used as a path parameter in a TypedGoRoute, go_router_builder produces a build error.
Code:
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
part 'routes.g.dart';
extension type const ArticleId(String value) {}
@TypedGoRoute<RootRoute>(
path: '/articles',
routes: [TypedGoRoute<ArticleRoute>(path: ':id')],
)
class RootRoute extends GoRouteData with _$RootRoute {
const RootRoute();
@override
Widget build(BuildContext context, GoRouterState state) {
return const Placeholder();
}
}
class ArticleRoute extends GoRouteData with _$ArticleRoute {
const ArticleRoute({required this.id});
final ArticleId id;
@override
Widget build(BuildContext context, GoRouterState state) {
return const Placeholder();
}
}Error:
$ dart run build_runner build -d
5s go_router_builder on 2 inputs: 1 skipped, 1 no-op; spent 4s analyzing
0s source_gen:combining_builder on 2 inputs: 2 skipped
Failed to build with build_runner in 6s; wrote 0 outputs.
log output for go_router_builder on lib/routes.dart
E The parameter type `ArticleId` is not supported.
package:builder_extension_type/routes.dart:22:37
╷
22 │ const ArticleRoute({required this.id});
│ ^^
╵Proposal
As documented here, go_router_builder currently supports path parameter types like String and int:
https://github.com/flutter/packages/tree/main/packages/go_router_builder#type-conversions
I propose extending this support to extension type. Here is an image of the generated code.
mixin _$ArticleRoute on GoRouteData {
static ArticleRoute _fromState(GoRouterState state) =>
ArticleRoute(id: state.pathParameters['id']! as ArticleId);
ArticleRoute get _self => this as ArticleRoute;
@override
String get location =>
GoRouteData.$location('/articles/${Uri.encodeComponent(_self.id.toString())}');
@override
void go(BuildContext context) => context.go(location);
@override
Future<T?> push<T>(BuildContext context) => context.push<T>(location);
@override
void pushReplacement(BuildContext context) =>
context.pushReplacement(location);
@override
void replace(BuildContext context) => context.replace(location);
}