A utility for easily repeating a promise-based task, until it succeeds. Works both in Node and in the browser.
Installation
$ npm install repeat-promise-until-resolvedTable of Contents
Examples
Usage
In a node-based environment:
const repeatPromiseUntilResolved = require('repeat-promise-until-resolved'); If you're using it in the browser, without any build system, simply expose it to the global object:
<script src="node_modules/repeat-promise-until-resolved/index.js"></script>
Basic example
const repeatPromiseUntilResolved = require('repeat-promise-until-resolved');
const axios = require('axios');
(async()=>{
//Create a function that returns a promise, which you want to repeat until resolved. If you're not familiar with async functions, note that they return a promise.
async function promiseFactory() {
const { data } = await axios('https://jsonplaceholder.typicode.com/todos/1')
console.log(data)
}
try {
//Pass the promise-producing function, and an optional config object. The default maxAttempts value is 3.
await repeatPromiseUntilResolved(promiseFactory, { maxAttempts: 3});//Will be performed 3 times at most, until it finally fails.
} catch (error) {//An error will be thrown, only after the final failing attempt.
console.log('final fail',error)
}
})()
Additional configuration
(async()=>{
async function promiseFactory() {
const { data } = await axios('https://jsonplaceholder.typicode.com/todos/1')
console.log('success',data)
}
//Hook into each attempt, and receive the attempt number
const onAttempt = (attempt) => {
console.log(attempt);
}
//Hook into every error thrown, and receive the Error object and the attempt number.
const onError = (error, attempt) => {
console.log(error.message, attempt);
}
try {
//Limit to 5 attempts, and create a delay of 2 seconds between each attempt. timeout: Wait up to 5 seconds for each promise to resolve, until it's manually rejected(and retried)
//Also pass functions to the hooks.
await repeatPromiseUntilResolved(promiseFactory, { maxAttempts: 5, delay: 2000, timeout:5000, onAttempt, onError });
} catch (error) {
console.log('final fail',error)
}
})()
API
function repeatPromiseUntilResolved(promiseFactory,config):Promise
| Parameter | type | Description |
|---|---|---|
| promiseFactory | function | A function that returns the promise you want to "repeat" |
| config | object | A configuration and hook object. Not required |
| config.maxAttempts | number | Number of maximum attempts(including the first one) |
| config.delay | number | Number of milliseconds to wait between each retry. Useful in network requests |
| config.timeout | number | Number of milliseconds to wait, until the promise is manually rejected. Default is 8000 |
| config.onAttempt | function | Hook into each attempt. Receives the number of the current attempt as an argument |
| config.onError | function | Hook into each failed attempt. Receives the Error object as an argument |
| config.shouldStop | function | Hook into each failed attempt. Receives the Error object as an argument. Return true, if you want the repetition to stop |