Discussion on: Which functions/methods do you...

[Daniel Fyhr]

This little snippet to sleep

const delay = (ms) => new Promise((r) => setTimeout(r, ms));
await delay(1000);

[Timo]

I've never used that one xD

[Camco]

Love this

[JoelBonetR 🥇]

I'm afraid to ask where you need this one 😂😂

[Daniel Fyhr]

I've used it for polling. And... Sometimes you got to do what you got to do 😂

[JoelBonetR 🥇]

Hahaha no judgements. Still I let you some polling thingy I had here that may be more suitable:

const poll = async ({ fn, validate, interval, maxAttempts }) => {
  let attempts = 0;

  const executePoll = async (resolve, reject) => {
    const result = await fn();
    attempts++;

    if (validate(result)) {
      return resolve(result);
    } else if (maxAttempts && attempts === maxAttempts) {
      return reject(new Error('Exceeded max attempts'));
    } else {
      setTimeout(executePoll, interval, resolve, reject);
    }
  };

  return new Promise(executePoll);
};

poll function is a higher-order function that returns a function, executePoll.

executePoll function returns a promise and will run recursively until the condition is met.

Args explained:

fn: an API request (or another async thingy that suits for this polling).

validate: Test function to see if the data matches what we want, in which case it will end the poll.

interval: To specify how much it wait between poll requests.

maxAttempts: how many tries before throwing an error.

😁

[Rishad Omar]

I couldn't sleep last night and read this comment at 3am. Coincidentally, today, I needed this poll. Works great in my usEffect().
The only thing that caught me is that the parameters to the above poll function are in a class, instead of individual parameters.
Thanks for the code!

[JoelBonetR 🥇]

Didn't get the meaning of the sentence "The only thing that caught me is that the parameters to the above poll function are in a class, instead of individual parameters." still glad to see it helped you 😁

[Rishad Omar]

Apologies, I didn't explain correctly.
Initially, I called the poll function incorrectly as follows:

poll(myFunction, myValidate, myInterval, myMaxAttempts)

The correct method (using your code) is:

poll({
   fn: myFunction,
   validate: myValidate,
   interval: myInterval,
   maxAttempts: myMaxAttempts
})

[JoelBonetR 🥇]

Oh! nothing to do with classes it's just it receives an object but this is opinionated as I prefer to have the object structure for those "config" thingies, you can simply delete the brackets on the function declaration like that:

const poll = async ( fn, validate, interval, maxAttempts ) => {

and we should be good 😁

[Alex Parra]

Nice snippet.
The new Promise callback should not be an async function. By passing an async fn to new Promise you’re “double promising”.
Refactoring to not depend on resolve/reject would solve that.
Or maybe

new Promise((res, rej) => executePoll(res, rej))

[JoelBonetR 🥇]

Having it as async lets you handle the response, the error and any action to perform either it went OK or KO, so it can be customised specifically on it's environment.

myPoll.then( res => res ).catch( err => console.error( 'myCustomError', err )).finally( () => setExecutionFinished(true));

instead handling it as generic inside the polling function.

But sure you can tweak it as you wish to fullfill your needs 😄

[Rafał Goławski]

This one is pretty neat, I also use it sometimes to "mock" API responses like this 👇

await delay(1000).then(() => ([ { id: 1, data: "some data" } ]))

[Daniel Fyhr]

I love that one!