retri

A lightweight, configurable retry utility for async JavaScript. Features built-in support for backoff strategies, jitter, lifecycle hooks, and abort signals.

Features

• Configurable retries: Set max attempts, delay, and custom retry logic.
• Backoff strategies: Built-in support for fixed, linear, and exponential backoff.
• Jitter: Add randomness to delays to prevent thundering herd problems.
• Lifecycle Hooks: Track execution using onSuccess, onFail, and onRetry callbacks.
• Abort controller support: Cancel pending retries seamlessly using an AbortSignal.
• Custom retry logic: Determine dynamically whether an error is retryable using shouldRetry.

Installation

npm install retri

Usage

Basic Usage

import { retry } from 'retri';

async function fetchData() {
    const response = await fetch('https://api.example.com/data');
    if (!response.ok) throw new Error('Network error');
    return response.json();
}

// Retries up to 3 times (4 attempts total) with a fixed delay of 300ms
const data = await retry(fetchData);

Advanced Usage with Options

import { retry } from 'retri';

const abortController = new AbortController();

const options = {
    retries: 5,                  // Number of retry attempts (default: 3)
    delay: 500,                  // Initial delay in ms (default: 300)
    backoff: 'exponential',      // Backoff strategy: 'fixed', 'linear', or 'exponential' (default: 'fixed')
    factor: 2,                   // Multiplier for exponential backoff (default: 2)
    jitter: 0.2,                 // Jitter fraction (e.g., 0.2 means +/- 20% randomness)
    signal: abortController.signal, // Pass an AbortSignal to cancel early

    // Only retry on specific errors
    shouldRetry: (error, ctx) => {
        if (error.message.includes('Fatal')) return false; // Stop retrying
        return true;
    },

    // Lifecycle hooks
    onRetry: (ctx) => console.log(`Retrying... attempt ${ctx.attempt}. Errors left: ${ctx.retriesLeft}`),
    onSuccess: (ctx) => console.log(`Success on attempt ${ctx.attempt}! Time elapsed: ${ctx.timeElapsed}ms`),
    onFail: (ctx) => console.error(`Failed after ${ctx.attempt} attempts.`)
};

try {
    const result = await retry(fetchData, options);
} catch (error) {
    console.error('Operation failed:', error);
}

API Reference

retry(fn, options?)

Executes the async function fn and automatically retries it upon failure according to the provided options.

Arguments

• fn (Function): An asynchronous function that returns a Promise.
• options (Object): Configuration options (optional).

Options Available

Option	Type	Default	Description
retries	number	3	Maximum number of retries (total attempts will be retries + 1).
delay	number	300	Initial delay between attempts, in milliseconds.
backoff	string	'fixed'	Strategy for calculating delay: 'fixed', 'linear', or 'exponential'.
factor	number	2	Multiplier used when backoff is 'exponential'.
jitter	number	0	Fraction (0 to 1) of jitter to apply to the delay. 0.2 adds ±20% randomness.
signal	AbortSignal	null	Used to abort the retry process entirely. Throws a DOMException error.
shouldRetry	Function	() => true	Predicate function (error, context) returning a boolean. If false, retries are aborted.
onSuccess	Function	-	Hook executed when fn completes successfully.
onRetry	Function	-	Hook executed right before a retry wait period begins.
onFail	Function	-	Hook executed when all retries are exhausted or shouldRetry returns false.

Context Object (ctx)

Lifecycle hooks (onSuccess, onRetry, onFail) and the shouldRetry predicate receive a context object with useful properties:

• ctx.attempt: The current attempt number (starts at 1).
• ctx.retriesLeft: Number of remaining allowed retries.
• ctx.timeElapsed: Milliseconds elapsed since the primary execution started.
• ctx.error: The most recent error encountered (is null in onSuccess).
• ctx.result: The returned result (only available in onSuccess).
• ctx.errors: An array of all errors encountered so far (available in onFail).

Errors

When exceptions bubble out of the retry utility, they might be custom Error classes depending on the reason:

• RetriError: Thrown when maximum retries are exceeded or if shouldRetry returns false. Contains properties .attempt, .errors (array of all caught errors), and .lastError.
• DOMException: Standard DOMException with name "AbortError" is thrown when the provided AbortSignal is aborted.

Contributing

retri is an open-source project, and contributions are welcome.

• Found a bug? → Open an issue
• Have a feature idea? → Start a discussion
• Want to improve code or docs? → Open a pull request

GitHub Repository:
👉 https://github.com/GLXALOKESH/retri

The issue tracker is open to everyone — no contribution is too small.

Stability & Versioning

retri follows semantic versioning:

• PATCH: Bug fixes
• MINOR: New features (may introduce new options)
• MAJOR: Breaking changes (will be clearly documented)

Breaking changes will be avoided where possible and clearly announced.

License

MIT