import { type Falsy } from "https://deno.land/x/rxjs@v1.0.2/mod.ts";
A simple type to represent a gamut of "falsy" values... with a notable exception:
NaN
is "falsy" however, it is not and cannot be typed via TypeScript. See
comments here: https://github.com/microsoft/TypeScript/issues/28682#issuecomment-707142417