diff --git a/src/mixin.ts b/src/mixin.ts
new file mode 100644
index 0000000000000..184a50fdb0f7e
--- /dev/null
+++ b/src/mixin.ts
@@ -0,0 +1,5 @@
+type ClassConstructor = new(...args: unknown[]) => {};
+
+function mixin<C extends ClassConstructor>(Class: C) {
+  return class extends Class {};
+}
\ No newline at end of file