Bug Fixed: Own function properties are not copied

package.json

@@ -1,6 +1,6 @@
 {
   "name": "class-logger",
-  "version": "1.0.3",
+  "version": "1.1.0",
   "description": "Boilerplate-free decorator-based class logging",
   "keywords": [
     "decorator",
@@ -23,7 +23,7 @@
     "type": "git",
     "url": "git+https://github.com/keenondrums/class-logger.git"
   },
-  "author": "keenondrums (andrey[email protected])",
+  "author": "keenondrums (andrey@goncharov.page)",
   "license": "MIT",
   "bugs": {
     "url": "https://github.com/keenondrums/class-logger/issues"

src/class-wrapper.service.spec.ts

@@ -162,6 +162,24 @@ describe(ClassWrapperService.name, () => {
       expect(spyLogError).toBeCalledWith(spyFormatterEndMockRes)
     }
 
+    test('copies own properties of a target function', () => {
+      const testProp = 'test'
+      const testPropVal = Symbol()
+
+      const fn = jest.fn() as any
+      fn[testProp] = testPropVal
+
+      const config = ConfigService.config
+      const className = 'Test'
+      const propertyName = 'test'
+      const classInstance = {}
+
+      const classWrapperService: any = new ClassWrapperService()
+      const fnWrapped = classWrapperService.wrapFunction(config, fn, className, propertyName, classInstance)
+
+      expect(fnWrapped[testProp]).toBe(testPropVal)
+    })
+
     describe('synchronous target function', () => {
       test('logs success', async () => {
         const fnRes = Symbol()

src/class-wrapper.service.ts

@@ -28,7 +28,7 @@ export class ClassWrapperService {
     const classWrapper = this
     // Use non-arrow function to allow dynamic context
     // tslint:disable-next-line only-arrow-functions
-    return function(this: any, ...args: any[]) {
+    const res = function(this: any, ...args: any[]) {
       const messageStart = config.formatter.start({
         args,
         classInstance,
@@ -76,6 +76,13 @@ export class ClassWrapperService {
         throw error
       }
     } as T
+
+    // Functions are objects as well. They might have own properties.
+    for (const prop of Object.keys(fn) as Array<keyof T>) {
+      res[prop] = fn[prop]
+    }
+
+    return res
   }
 
   protected isPromise(val: any) {