Uncaught TypeError: Class extends value #<Object> is not a constructor or null

[viv3kc]

Whenever I import Sema or RateLimit.

i.e import { RateLimit, Sema } from 'async-sema';

I'm getting the following error:

Uncaught TypeError: Class extends value #<Object> is not a constructor or null

Is there any workaround for it?

Thanks.

[OlliV]

Is this an ECMAScript import? I think a commonJS require is needed.