installed with npm, import added in my polymer3 page, but not showing :(

[fireplace009]

Describe the bug
Not sure if it's a bug ... just wondering why it's not working

To Reproduce
Steps to reproduce the behavior:

1. I installed by : npm install @wanoo21/countdown-time
2. I added in my PolymerElement the import: import "@wanoo21/countdown-time";
3. Added the tag in my html
4. I do not see the countdown :(

Desktop (please complete the following information):

• OS: Fedora
• Browser chrome

Maybe
My project does not have typescript ... could that be the reason?