/**

* @title Exponential backoff

* @difficulty intermediate

* @tags cli, deploy, web

* @run <url>

* @resource {https://en.wikipedia.org/wiki/Exponential_backoff} Wikipedia: Exponential backoff

* @resource {https://jsr.io/@std/async/doc/~/retry} Doc: @std/async > retry

* @group Advanced

*

* Exponential backoff is a technique used in computer systems to handle retries and

* avoid overwhelming services. We can easily implement this by using the `retry`

* utility provided by the standard library.

*/

// Import the 'retry' utility from '@std/async'.

import { retry, RetryError, type RetryOptions } from "jsr:@std/async";

// A function that logs 'hello world' to the console and returns a rejected Promise.

const fn = () => {

console.log("hello world");

return Promise.reject("rejected");

};

// Configuration for retry options which will make sure that the function will be

// called at max 3 times before throwing an error. The first call to the function

// will be made immediately, the second call will happen after a delay of 10ms

// and the third/final call will be made after a delay of 20ms.

const options: RetryOptions = {

maxAttempts: 3,

minTimeout: 10,

multiplier: 2,

jitter: 0,

};

try {

// Wrap the function with the 'retry' utility along with the retry configuration.

await retry(fn, options);

} catch (err) {

// When max attempts are exhausted, a RetryError is thrown containing the original

// rejection reason 'rejected' as its cause property.

if (err instanceof RetryError) {

console.log("Retry error :", err.message);

console.log("Error cause :", err.cause);

}

}