From a065daec1e88b3ff48f3008ceaef9e55f223ff43 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Wed, 14 Feb 2024 21:57:48 +0100
Subject: [PATCH] extendAbstract

---
 src/TraitBuilder.ts | 13 +++++++++++++
 src/tests.ts        | 16 ++++++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/TraitBuilder.ts b/src/TraitBuilder.ts
index 6c43e8b..24d62ea 100644
--- a/src/TraitBuilder.ts
+++ b/src/TraitBuilder.ts
@@ -57,6 +57,19 @@ export class TraitBuilder<
         )
     }
 
+    extendAbstract<
+        A extends Abstract
+    >(
+        abstract: (Super: AbstractClass<Abstract>) => AbstractClass<A, []>
+    ) {
+        return new TraitBuilder(
+            this.traitSuperExpression,
+            {} as A,
+            this.traitStaticAbstract,
+            this.traitApply,
+        )
+    }
+
     implement<
         ImplClassWithAbstract extends (
             Class<Abstract, []> &
diff --git a/src/tests.ts b/src/tests.ts
index 914ef53..688a352 100644
--- a/src/tests.ts
+++ b/src/tests.ts
@@ -28,14 +28,22 @@ const Identifiable = <ID>() => trait
     .build()
 
 const StatefulSubscription = trait
-    .abstract<{
-        readonly isStatefulSubscription: true
-        readonly status: (
+    // .abstract<{
+    //     readonly isStatefulSubscription: true
+    //     readonly status: (
+    //         { _tag: "awaitingPayment" } |
+    //         { _tag: "active", activeSince: Date, expiresAt?: Date } |
+    //         { _tag: "expired", expiredSince: Date }
+    //     )
+    // }>()
+    .extendAbstract(Super => class extends Super {
+        readonly isStatefulSubscription!: true
+        readonly status!: (
             { _tag: "awaitingPayment" } |
             { _tag: "active", activeSince: Date, expiresAt?: Date } |
             { _tag: "expired", expiredSince: Date }
         )
-    }>()
+    })
     .build()
 
 type StatefulSubscriptionClass = Trait.Class<typeof StatefulSubscription>