Hierarchical dependency injection framework

Adapted from this experiment:
https://stackblitz.com/edit/vitejs-vite-6tenu8?file=src%2Fapp.ts

utility/src/lib/types.ts

@@ -1,7 +1,23 @@
+export interface Ctor<T, Args extends any[] = any[]> {
+	new (...args: Args): T;
+	prototype: T;
+}
+
+export type AbstractCtor<T, Args extends any[] = any[]>
+	= (abstract new (...args: Args) => T)
+	& { prototype: T }
+	;
+
 export interface Fn<Args extends any[] = [], R = void> {
 	(...args: Args): R;
 }
 
+export interface Method<T, Args extends any[] = any[], R = any> {
+	(this: T, ...args: Args): R;
+}
+
+export type Opt<T> = T | null | undefined;
+
 export type WithOpt<T, K extends keyof T>
 	= Omit<T, K>
 	& Partial<Pick<T, K>>