@dyaa/async-retry

@dyaa/async-retry

Table of Contents

• Problem
• Installation
• Usage
• License

Problem

We needed a utility that helps us to retry an async function on it's Failure/Rejection and to be able to control the number of retries and the time interval between each retry also to block the retries in case of some array with http status codes provided!

Installation

yarn add @dyaa/async-retry

Or if you prefer npm!

npm i @dyaa/async-retry

Usage

import asyncRetry from '@dyaa/async-retry';

asyncRetry expects two parameters

• The first parameter is a function that returns a Promise.
• The second parameter is an options object (all of them are optional).

Options	Type	Optional?	Default	Description
retries	number	optional	5retries	number of retries
interval	number	optional	5000ms	base interval between retries
dontRetry	function	optional	() => false	A function that returns a boolean value. This boolean value is to check if we want the retry to continue or not
onComplete	function	optional	null	.
onFailure	function	optional	null	.
onRetry	function	optional	null	.

Example

import asyncRetry from '@dyaa/async-retry';
// import initRealtimeService action...
// import ResolvedType

/*
As we said first parameter is a function that returns a promise.
so we gonna try with function that dispatches an action for this example
*/
const fn = () => dispatch(initRealtimeService());

asyncRetry<ResolvedType, NetworkError>(fn, {
	retries: 2, // default is 5
	interval: 2000, // default is 5000
	dontRetry: (e: NetworkError) => [404, 503].includes(e.status),
}).then().catch();

The example above says that we gonna retry two times the function in case of it's Failure/Rejection with base interval of 2000 but if we got status codes 404 or 503 we won't retry at all.

Backoff formula

/**
 * Backoff formula for more info checkout
 * https://en.wikipedia.org/wiki/Exponential_backoff
 * E -> factor
 * c -> number of trys
 * I -> Interval
 * 
 * E(c) = (2^c - 1) / 2
 * E(c) * I
 * @param {number} times - The number of which retry.
 * @param {number} interval - Time interval of last retry in ms.
 * @returns {number} - Number of next retry interval in ms.
 */

Inspiration

• README structure Kent C. Dodds's Tweet

Thanks

• Christian Gill Github Twitter

License

MIT License © dyaa