Import 'when' in TypeScript

Question

Is there a way to make use of the when framework in TypeScript?

In JavaScript I can import it like this:

import when from 'when';

But doing the same in TypeScript leads to this error:

Cannot find module 'when'. Did you mean to set the 'moduleResolution' option to 'node', or to add aliases to the 'paths' option? ts(2792)

I am using it to complete all the promises within a then clause:

.then(employeePromises => {
    return when.all(employeePromises);
});