src/index.ts

@@ -34,11 +34,16 @@ export type TraitApplier<
  * Unwraps the type of the class from a given trait.
  * @template T - The trait type.
  */
-export type UnwrapTraitC<T> =
+export type TraitClass<T> =
     T extends Trait<infer C>
         ? C
         : never
 
+export type TraitInstance<T> =
+    T extends Trait<infer C>
+        ? InstanceType<C>
+        : never
+
 
 /**
  * Creates a trait using the provided trait applier function.
@@ -90,7 +95,7 @@ export type UnwrapTraitC<T> =
  *     trait(Parent => {
  *         abstract class ImplementsIdentifiable extends extendsAndExpresses(
  *             Parent,
- *             [Identifiable<ID>()],
+ *             Identifiable<ID>(),
  *         ) {
  *             id: ID = defaultID
  *
@@ -123,7 +128,10 @@ export function trait<
  * @example
  * Extends a superclass and applies traits:
  * ```ts
- * class User extends extendsAndExpresses(Entity, [Identifiable<bigint>(), Permissible]) {
+ * class User extends extendsAndExpresses(Entity,
+ *     Identifiable<bigint>(),
+ *     Permissible,
+ * ) {
  *     readonly id: bigint
  *
  *     constructor(id: bigint) {
@@ -138,7 +146,7 @@ export function extendsAndExpresses<
     Traits extends readonly Trait<any>[],
 >(
     extend: C,
-    traits: Traits,
+    ...traits: Traits
 ) {
     return traits.reduce(
         (previous, trait) => trait(previous),
@@ -147,10 +155,8 @@ export function extendsAndExpresses<
         AbstractClass<
             InstanceType<C> &
             UnionToIntersection<
-                InstanceType<
-                    UnwrapTraitC<
-                        Traits[number]
-                    >
+                TraitInstance<
+                    Traits[number]
                 >
             >,
 
@@ -160,7 +166,7 @@ export function extendsAndExpresses<
         StaticMembers<C> &
         StaticMembers<
             UnionToIntersection<
-                UnwrapTraitC<
+                TraitClass<
                     Traits[number]
                 >
             >
@@ -191,5 +197,5 @@ export function expresses<
 >(
     ...traits: Traits
 ) {
-    return extendsAndExpresses(Object, traits)
+    return extendsAndExpresses(Object, ...traits)
 }

src/tests.ts

@@ -23,7 +23,7 @@ const ImplementsIdentifiable = <ID>(defaultID: ID) =>
     trait(Parent => {
         abstract class ImplementsIdentifiable extends extendsAndExpresses(
             Parent,
-            [Identifiable<ID>()],
+            Identifiable<ID>(),
         ) {
             id: ID = defaultID