Project setup

src/util/class.ts

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+import { AbstractClass } from "type-fest"
+
+
+/**
+ * Represents an array of instances corresponding to the provided classes.
+ * @template Classes - An array of classes extending AbstractClass.
+ */
+export type ClassesInstances<Classes extends readonly AbstractClass<any>[]> = (
+    Classes extends [infer Class, ...infer Rest]
+        ? Class extends AbstractClass<any>
+            ? Rest extends AbstractClass<any>[]
+                ? [InstanceType<Class>, ...ClassesInstances<Rest>]
+                : never
+            : never
+        : []
+)
+
+/**
+ * Represents an intersection of instances of the provided classes.
+ * @template Classes - An array of classes extending AbstractClass.
+ */
+export type ClassesInstancesIntersection<Classes extends readonly AbstractClass<any>[]> = (
+    Classes extends [infer Class, ...infer Rest]
+        ? Class extends AbstractClass<any>
+            ? Rest extends AbstractClass<any>[]
+                ? InstanceType<Class> & ClassesInstancesIntersection<Rest>
+                : never
+            : never
+        : {}
+)
+
+/**
+ * Represents the static members of a class.
+ * @template Class - A class extending AbstractClass.
+ */
+export type StaticMembers<Class extends AbstractClass<any>> = (
+    Omit<Class, "prototype">
+)
+
+/**
+ * Represents an array of static members corresponding to the provided classes.
+ * @template Classes - An array of classes extending AbstractClass.
+ */
+export type ClassesStaticMembers<Classes extends readonly AbstractClass<any>[]> = (
+    Classes extends [infer Class, ...infer Rest]
+        ? Class extends AbstractClass<any>
+            ? Rest extends AbstractClass<any>[]
+                ? [StaticMembers<Class>, ...ClassesStaticMembers<Rest>]
+                : never
+            : never
+        : []
+)
+
+/**
+ * Represents an intersection of static members of the provided classes.
+ * @template Classes - An array of classes extending AbstractClass.
+ */
+export type ClassesStaticMembersIntersection<Classes extends readonly AbstractClass<any>[]> = (
+    Classes extends [infer Class, ...infer Rest]
+        ? Class extends AbstractClass<any>
+            ? Rest extends AbstractClass<any>[]
+                ? StaticMembers<Class> & ClassesStaticMembersIntersection<Rest>
+                : never
+            : never
+        : {}
+)

src/util/index.ts

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+export * from "./class"
+export * from "./inheritance"
+export * from "./trait"

src/util/inheritance.ts

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+/**
+ * Represents the common keys between two types.
+ * @template A - The first type.
+ * @template B - The second type.
+ */
+export type CommonKeys<A, B> = Extract<keyof A, keyof B>
+
+/**
+ * Merges an inheritance tree defined by an array of types, considering overrides.
+ * @template T - An array of types representing the inheritance tree.
+ */
+export type MergeInheritanceTree<T extends readonly any[]> = (
+    T extends [infer Super, infer Self, ...infer Rest]
+        ? Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
+            ? MergeInheritanceTree<[
+                Omit<Super, CommonKeys<Self, Super>> & Self,
+                ...Rest,
+            ]>
+            : never
+        : T extends [infer Self]
+            ? Self
+            : void
+)
+
+/**
+ * Merges an inheritance tree defined by an array of types without allowing overrides.
+ * @template T - An array of types representing the inheritance tree.
+ */
+export type MergeInheritanceTreeWithoutOverriding<T extends readonly any[]> = (
+    T extends [infer Super, infer Self, ...infer Rest]
+        ? Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
+            ? MergeInheritanceTreeWithoutOverriding<[
+                Super & Self,
+                ...Rest,
+            ]>
+            : never
+        : T extends [infer Self]
+            ? Self
+            : void
+)

src/util/trait.ts

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+import { Trait, TraitClass } from ".."
+
+
+/**
+ * Represents an array of classes corresponding to the provided traits.
+ * @template Traits - An array of traits extending Trait<any>.
+ */
+export type TraitsClasses<Traits extends readonly Trait<any>[]> = (
+    Traits extends [infer T, ...infer Rest]
+        ? T extends Trait<any>
+            ? Rest extends Trait<any>[]
+                ? [TraitClass<T>, ...TraitsClasses<Rest>]
+                : never
+            : never
+        : []
+)