exponential-backoff
A utility that allows retrying a function with an exponential delay between attempts.
Installation
npm i exponential-backoff
Usage
The backOff<T>
function takes a promise-returning function to retry, and an optional BackOffOptions
object. It returns a Promise<T>
.
function backOff<T>(
request: () => Promise<T>,
options?: BackOffOptions
): Promise<T>;
Here is an example retrying a function that calls a hypothetical weather endpoint:
import { backOff } from "exponential-backoff";
function getWeather() {
return fetch("weather-endpoint");
}
async function main() {
try {
const response = await backOff(() => getWeather());
// process response
} catch (e) {
// handle error
}
}
main();
Migrating across major versions? Here are our breaking changes.
BackOffOptions
-
delayFirstAttempt?: boolean
Decides whether the startingDelay
should be applied before the first call. If false
, the first call will occur without a delay.
Default value is false
.
-
jitter?: JitterType | string
Decides whether a jitter should be applied to the delay. Possible values are full
and none
.
Default value is none
.
-
maxDelay?: number
The maximum delay, in milliseconds, between two consecutive attempts.
Default value is Infinity
.
-
numOfAttempts?: number
The maximum number of times to attempt the function.
Default value is 10
.
Minimum value is 1
.
-
retry?: (e: any, attemptNumber: number) => boolean | Promise<boolean>
The retry
function can be used to run logic after every failed attempt (e.g. logging a message, assessing the last error, etc.). It is called with the last error and the upcoming attempt number. Returning true
will retry the function as long as the numOfAttempts
has not been exceeded. Returning false
will end the execution.
Default value is a function that always returns true
.
-
startingDelay?: number
The delay, in milliseconds, before executing the function for the first time.
Default value is 100
ms.
-
timeMultiple?: number
The startingDelay
is multiplied by the timeMultiple
to increase the delay between reattempts.
Default value is 2
.