@wuyuchentr/fetch-retry-polyfill

Auto-retry wrapper for fetch with exponential backoff and custom retry conditions. < 1 KB, zero dependencies.

Install

npm install @wuyuchentr/fetch-retry-polyfill

Usage

const { fetchRetry } = require('@wuyuchentr/fetch-retry-polyfill');

// Basic — retry up to 3 times on network errors / 5xx
const res = await fetchRetry('https://api.example.com/data');

// Custom retries and delay
const res = await fetchRetry('https://api.example.com/data', {
  retries: 5,
  retryDelay: 500,
});

Retry on specific status codes

const res = await fetchRetry('https://api.example.com/data', {
  retries: 3,
  retryOn: [429, 502, 503, 504],
});

Custom retry condition

const res = await fetchRetry('https://api.example.com/data', {
  retries: 3,
  retryOn: (attempt, error, response) => {
    if (error) return true;                       // network error → retry
    if (response && response.status === 429) return true;  // rate limit → retry
    if (attempt < 2 && response && response.status >= 500) return true; // 5xx, retry twice
    return false;
  },
});

API

fetchRetry(url, options?)

Same signature as native fetch(url, init), with extra options:

| Option | Default | Description | |--------|---------|-------------| | retries | 3 | Max retry attempts | | retryDelay | 1000 | Base delay in ms (exponential: delay × 2^attempt) | | retryOn | — | Array of status codes, or (attempt, error, response) => boolean |

Default retry condition:

• Network errors: always retry
• HTTP 5xx: retry
• HTTP 4xx: no retry

All other init options (method, headers, body, etc.) are passed through to fetch.