How To Execute This HTML File

[king87515]

I download this project to my local workspace. I execute it by "http-server". Then open index.html file in example folder, and it consoles some errors below.
Uncaught SyntaxError: Unexpected token 'export' ---weatherwheel.js:3
Uncaught (in promise) ReferenceError: WeatherWheel is not defined at (index):50 ---(index):50

I wonder whether I need to build any environment and how to fix it then can work correctly, thanks a lot.