How can I call a function defined in an Angular component in a JavaScript file?

In a .ts file, I have the following code

export class SomeClass {
    .
    .
    .
    public someMethod() {
        ...
    }
}

I want to call this someMethod method in a .js file.

I tried

import { SomeClass } from '../../../../SomeClass';
.
.
.
SomeClass.someMethod();

but got the following error:

someMethod is not a function

Do I have to make the method static?

I prefer not because it calls other methods and I will have to make all of them static.

Can I create an instance of this class in the .js file?

Thanks!