fix: nil error response

Author: mnavarrocarter

function.go

@@ -34,7 +34,11 @@ func reflectFunc(fn any) *reflectedFn {
 	case 1:
 		if t.Out(0).Implements(errorType) {
 			rFn.outFn = func(out []reflect.Value) (interface{}, error) {
-				return nil, out[0].Interface().(error)
+				if err, ok := out[0].Interface().(error); ok {
+					return nil, err
+				}
+
+				return nil, nil
 			}
 		} else {
 			rFn.outFn = func(out []reflect.Value) (interface{}, error) {

handler_test.go

@@ -134,6 +134,17 @@ func TestHandler(t *testing.T) {
 			expectedResponse: []byte(`{"status":500,"details":"there was an error"}` + "\n"),
 			expectedStatus:   http.StatusInternalServerError,
 		},
+		{
+			name: "nil error response",
+			req: func() *http.Request {
+				return httptest.NewRequest(http.MethodGet, "https://example.com", mustOpen(t, "valid.json"))
+			}(),
+			handler: func() error {
+				return nil
+			},
+			expectedResponse: []byte(""),
+			expectedStatus:   http.StatusNoContent,
+		},
 		{
 			name: "panic response",
 			req: func() *http.Request {