From f39a6b9acb1df9247e65b3b0340290c3ddac71f7 Mon Sep 17 00:00:00 2001
From: ersimont <8042088+ersimont@users.noreply.github.com>
Date: Fri, 27 Nov 2020 08:22:41 -0500
Subject: [PATCH] feat(js-core): add `Constructor` type to support the mixin
 pattern

---
 projects/integration/src/app/api-tests/js-core.spec.ts | 6 ++++++
 projects/js-core/src/lib/objects/constructor.ts        | 4 ++++
 projects/js-core/src/lib/objects/index.ts              | 1 +
 3 files changed, 11 insertions(+)
 create mode 100644 projects/js-core/src/lib/objects/constructor.ts

diff --git a/projects/integration/src/app/api-tests/js-core.spec.ts b/projects/integration/src/app/api-tests/js-core.spec.ts
index be2af844..f2b50131 100644
--- a/projects/integration/src/app/api-tests/js-core.spec.ts
+++ b/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();
     });
diff --git a/projects/js-core/src/lib/objects/constructor.ts b/projects/js-core/src/lib/objects/constructor.ts
new file mode 100644
index 00000000..20367bcf
--- /dev/null
+++ b/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;
diff --git a/projects/js-core/src/lib/objects/index.ts b/projects/js-core/src/lib/objects/index.ts
index c9b9b014..c1744d70 100644
--- a/projects/js-core/src/lib/objects/index.ts
+++ b/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';