fetch.js

const retry = require('async-retry');
const _fetch = require('isomorphic-fetch');
const createDebug = require('debug');

const debug = createDebug('iheart:fetch');

const defaultRetryOpts = {
  retries: 10,
  minTimeout: 500,
  onRetry(err) {
    debug('Retrying: %o', err);
  }
};

/**
 * Wrapper around `fetch` with `async-retry`.
 */
module.exports = function fetch(url, _opts) {
  const opts = Object.assign({}, defaultRetryOpts, _opts);

  return retry(async bail => {
    const method = (opts.method || 'GET').toUpperCase();
    debug(`${method} ${url}`);

    const res = await _fetch(url, opts);
    if (!res.ok) {
      const err = new Error(
        `${method} ${url} failed: HTTP status code ${res.status}`
      );
      if (Math.floor(res.status / 100) === 5) {
        // retry
        throw err;
      } else {
        // assume 4xx, user error, don't retry
        return bail(err);
      }
    }
    return res;
  }, opts);
};