@lifaon/rx-js-light/src/misc/helpers/read-observable-value.mjs

Blazing fast Observables

export function readObservableValue(subscribe, onNoValue) {
  let cachedValueReceived = false;
  let cachedValue;
  subscribe(value => {
    cachedValueReceived = true;
    cachedValue = value;
  })();
  return cachedValueReceived ? cachedValue : onNoValue();
}