Retrying made simple, easy, and async.

// Packages
const retry = require('async-retry')
const fetch = require('node-fetch')

await retry(async bail => {
  // if anything throws, we retry
  const res = await fetch('https://google.com')

  if (403 === res.status) {
    // don't retry upon 403
    bail(new Error('Unauthorized'))
    return
  }

  const data = await res.text()
  return data.substr(0, 500)
}, {
  retries: 5
})

retry(retrier : Function, opts : Object) => Promise

• The supplied function can be async or not. In other words, it can be a function that returns a Promise or a value.
• The supplied function receives two parameters
  1. A Function you can invoke to abort the retrying (bail)
  2. A Number identifying the attempt. The absolute first attempt (before any retries) is 1.
• The opts are passed to node-retry. Read its docs
  • retries: The maximum amount of times to retry the operation. Default is 10.
  • factor: The exponential factor to use. Default is 2.
  • minTimeout: The number of milliseconds before starting the first retry. Default is 1000.
  • maxTimeout: The maximum number of milliseconds between two retries. Default is Infinity.
  • randomize: Randomizes the timeouts by multiplying with a factor between 1 to 2. Default is true.
  • onRetry: an optional Function that is invoked after a new retry is performed. It's passed the Error that triggered it as a parameter.

• Guillermo Rauch (@rauchg) - ZEIT
• Leo Lamprecht (@notquiteleo) - ZEIT