How to import a node_module package in client

I was using CDN but needed some changes in the code so I install the npm package but dont know how to imported in my client view.

I tried:

import Calendar from './@event-calendar/core';

import TimeGrid from './@event-calendar/time-grid';

And also

import * as Calendar from './@event-calendar/core';

import * as TimeGrid from './@event-calendar/time-grid';

But I get error:

“Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of “text/html”. Strict MIME type checking is enforced for module scripts per HTML spec.”

Here is a Screen shot of my folder

And here of the node modules