@thi.ng/rstream/checks.js

Reactive streams & subscription primitives for constructing dataflow graphs / pipelines

import { implementsFunction } from "@thi.ng/checks/implements-function";
const isSubscriber = (x) => implementsFunction(x, "next");
const isSubscribable = (x) => implementsFunction(x, "subscribe");
const isSubscriptionLike = (x) => isSubscriber(x) && isSubscribable(x);
const isFirstOrLastInput = (mode, num) => mode === "first" || mode === "last" && !num;
export {
  isFirstOrLastInput,
  isSubscribable,
  isSubscriber,
  isSubscriptionLike
};