Make asynchronous paradigm optional

[yrd]

As mentioned in in #3, awaiting is not really required for all store types. It should be possible to define a store without using promises.

[rajmondx]

You can await any value, even if it's not a promise.

(async function() {
    console.log(await 3);
})();

To get back to the issue: In your case the only requirement should that the value is Callable (see Callable).

Distinguishing between Newable (e.g., new Whatever() – essentially a function returning this) and Callable is possible, but it’s beyond the scope of this library.