How do I import jStat in a Svelte project

I have a Typescript file in a Svelte project and would like use jStat https://github.com/jstat/jstat like the following:

export namespace Statistics
{


    export function cdfNormal (x:number, mean:number = 0, standard_deviation:number = 1) 
    {
        return jStat.normal.cdf(x,mean,standard_deviation); 
    }
};

I installed it via npm install --save jstat

I tried

import _ from "jstat";

and

var { jStat } = require('jstat')

But both didn't work.

The package says:

Currently jStat is exposed as j$ and jStat inside an object, rather than exported directly. This may confuse some module loaders, however should be easily remedied with the correct configuration.

But just calling jStat doesn't work either. What am I doing wrong?

The package should be imported as:

import jStat from 'jstat';

All the functions (e.g. mean) will be on the this default export object. The import has to be in the file using it.

The package supplies no types and no third party types (@types/jstat) seem to exist. You can type the module manually to any degree you like. E.g. add a file jstat.d.ts like this:

declare module 'jstat' {
    const jStat: {
        mean: (arr: number[]) => number;
        // ...
    };

    export default jStat;
}

Or just declare it any if you do not mind the lack of type safety.