enhancement(repository): Add hidden __factory property to mocks to differentiate them in conditional typing

Author: martinjlowm

src/repository/repository.ts

@@ -1,4 +1,5 @@
-type Factory = Function;
+// eslint-disable-next-line
+type Factory = (...args: any[]) => any;
 
 export class Repository {
   private readonly _repository: { [key: string]: Factory };
@@ -15,7 +16,36 @@ export class Repository {
   }
 
   public registerFactory(key: string, factory: Factory): void {
-    this._repository[key] = factory;
+    const proxy: Factory = new Proxy(
+      factory,
+      {
+        apply(target: Factory, _this: unknown, args: Parameters<Factory>): ReturnType<Factory> {
+          const mock: ReturnType<Factory> = target(...args);
+
+          if (typeof mock === 'undefined') {
+            return;
+          }
+
+          if (!(mock instanceof Object)) {
+            return mock;
+          }
+
+          if (typeof mock.__factory !== 'undefined') {
+            return mock;
+          }
+
+          Object.defineProperty(mock, '__factory', {
+            enumerable: false,
+            writable: false,
+            value: key,
+          });
+
+          return mock;
+        },
+      },
+    );
+
+    this._repository[key] = proxy;
   }
 
   public getFactory(key: string): Factory {