Helpers for working with ActionCable async on the client side

async_helpers.js

// Helpers

const MAX_WAIT = 10000;
const POLLING_RATE = 500;

export function timedOut (maxWait) {
  const startTime = Date.now();

  return () => Date.now() - startTime > maxWait;
}

export function waitUntilTime (timestamp, action) {
  const arrivalTime = timestamp - Date.now();

  setTimeout(action, arrivalTime);
}

export function waitUntil (condition, maxWait = MAX_WAIT) {
  return new Promise((resolve, reject) => {
    const isTimedOut = timedOut(maxWait);

    const waitInterval = setInterval(() => {
      if (condition()) {
        clearInterval(waitInterval);
        return resolve();
      }

      if (isTimedOut()) {
        clearInterval(waitInterval);
        return reject('Request timed out!');
      }
    }, POLLING_RATE);
  });
}

export function waitUntilConnected (channel) {
  return waitUntil(channel.consumer.connection.isOpen;
}
                   
// Demo Usecase:
                   
import cable from 'actioncable';

const consumer = cable.createConsumer();
const channel  = consumer.subscriptions.create({
  channel: "MyChannel",
  param: "something"
}, { /* ... */ });

waitUntilConnected(channel).then(() => {
  // Do something that relies on the channel being live
})

Am I misunderstanding the timing, or is this what the #connected callback provides in the js channel base class?