[IMP] typing: make app and mount method properly generic

src/component/component.ts

@@ -4,9 +4,25 @@ import type { ComponentNode } from "./component_node";
 //  Component Class
 // -----------------------------------------------------------------------------
 
+type Props = { [key: string]: any };
+
+interface StaticComponentProperties {
+  template: string;
+  defaultProps?: any;
+  props?: any;
+}
+
+export type ComponentConstructor<P extends Props = any, E = any> = (new (
+  props: P,
+  env: E,
+  node: ComponentNode
+) => Component<P, E>) &
+  StaticComponentProperties;
+
 export class Component<Props = any, Env = any> {
   static template: string = "";
   static props?: any;
+  static defaultProps?: any;
 
   props: Props;
   env: Env;