feat(js-core): add Constructor type to support the mixin pattern

projects/integration/src/app/api-tests/js-core.spec.ts

@@ -1,6 +1,7 @@
 import * as jsCore from '@s-libs/js-core';
 import {
   assert,
+  Constructor,
   convertTime,
   createBuilder,
   Debouncer,
@@ -30,6 +31,11 @@ import { keys } from '@s-libs/micro-dash';
 
 describe('js-core', () => {
   describe('public API', () => {
+    it('has Constructor', () => {
+      const constructor: Constructor<Date> = Date;
+      expect(constructor).toBeDefined();
+    });
+
     it('has TimeUnit', () => {
       expect(TimeUnit).toBeDefined();
     });

projects/js-core/src/lib/objects/constructor.ts

@@ -0,0 +1,4 @@
+/**
+ * Taken from the [typescript docs for mixins](https://www.typescriptlang.org/docs/handbook/mixins.html).
+ */
+export type Constructor<T = {}> = new (...args: any[]) => T;

projects/js-core/src/lib/objects/index.ts

@@ -1,3 +1,4 @@
+export { Constructor } from './constructor';
 export { createBuilder } from './create-builder';
 export { isEqualAtDepth } from './is-equal-at-depth';
 export { mapAsKeys } from './map-as-keys';