SubtraitAbstract

src/TraitExpression.ts

@@ -2,7 +2,30 @@ import { Fn, Pipe, Tuples } from "hotscript"
 import { AbstractClass, Class } from "type-fest"
 import { Trait } from "./Trait"
 import { TraitBuilder } from "./TraitBuilder"
-import { ExtendFn, SimplifyFn, StaticMembersFn } from "./util"
+import { ExtendFn, ExtendPlain, SimplifyFn, StaticMembersFn } from "./util"
+
+
+type SubtraitAbstract<Exp> = (
+    ExtendPlain<
+        MapTraitsToOwnAbstract<
+            TraitExpression.Traits<Exp>
+        >
+    >
+)
+type MapTraitsToOwnAbstract<T extends readonly any[]> = {
+    [K in keyof T]: Trait.OwnAbstract<T[K]>
+}
+
+type SubtraitStaticAbstract<Exp> = (
+    ExtendPlain<
+        MapTraitsToOwnStaticAbstract<
+            TraitExpression.Traits<Exp>
+        >
+    >
+)
+type MapTraitsToOwnStaticAbstract<T extends readonly any[]> = {
+    [K in keyof T]: Trait.OwnStaticAbstract<T[K]>
+}
 
 
 export class TraitExpression<
@@ -49,8 +72,8 @@ export class TraitExpression<
     ) {
         return new TraitBuilder(
             this,
-            {},
-            {},
+            {} as SubtraitAbstract<This>,
+            {} as SubtraitStaticAbstract<This>,
             Super => class extends Super {},
         )
     }

src/util/extend.ts

@@ -15,17 +15,21 @@ export type ExtendFn = Tuples.Reduce<ExtendReducerFn, {}>
 export type Extend<T extends readonly object[]> = Call<ExtendFn, T>
 
 
-export type ExtendPlain<T extends readonly any[]> = (
+export type ExtendPlain<T extends readonly object[]> = (
     T extends [infer Super, infer Self, ...infer Rest]
+        ? Rest extends object[]
             ? Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
                 ? ExtendPlain<[
                     Omit<Super, CommonKeys<Self, Super>> & Self,
                     ...Rest,
                 ]>
                 : never
+            : never
         : T extends [infer Self]
+            ? Self extends object
                 ? Self
-            : void
+                : never
+            : {}
 )