poll-generator

poll-generator

Polling async functions with AsyncGenerator.

why?

To poll functions without passing multiple callbacks to process different results.

Instalation & Usage

Install with npm

npm i --save poll-generator

Import and use it

import createPollGenerator from 'poll-generator'

const controller = new AbortController()

async function pollSomething() {
  const poller = createPollGenerator(
    api.apiCall.bind(api, ...someArgs),
    10,
    1000,
    controller
  )
  try {
    for await (const result of poller) {
      console.log(result)
      // do something based on the result
      // break; to get out of loop and continue with try block
      // or
      // return result; just return the result
    }
  } catch (e) {
    if (e.message === 'Poll interrupted') {
      // if poll was aborted
    }
    if (e.message === 'Tries exceeded') {
      // maxTries === 0
    }
    // every other error
  }
}

controller.abort() // call to end poll

Docs

Parameters

fn: () => any

Async function to be called. Use Function.prototype.bind to pass arguments.

maxTries: number

Number of times to call fn()

time: number

Delay between calls in milliseconds

controller: AbortController (optional)

Instance of AbortController

Customization

By default createPollGenerator throws 'Poll interrupted' and 'Tries ecxeeded' errors when poll is aborted or tries are exceeded. This behavior can be changed by importing and using customizePollGenerator function

// customPollGenerator.js

import { customizePollGenerator } from 'poll-generator'

// result of fn() is passed to a function so you can use it
function onAbort(result) {
  console.log(result)
}

function onTimeout(result) {
  console.log('no tries left', result)
}

const customPoll = customizePollGenerator(onAbort, onTimeout)

export default customPoll

import customPoll from './customPollGenerator'

async function pollSomething() {
  const poller = createPoll(fn, 10, 1000)
  ...
}