Async retry utility for Node

retry.js

const backoffFns = {
  constant: curDelay => curDelay,
  geometric: curDelay => curDelay * 2,
}

const defaultOpts = {
  maxTries: 2,
  delay: 0,
  backoff: 'constant',
  logger: console.log,
}

const defaultState = {
  tries: 0,
  delay: 0,
  errors: [],
}

async function retry (fn, opts, state) {
  opts  = Object.assign({}, defaultOpts,  opts)
  state = Object.assign({}, defaultState, state)
  try {
    await fn()
  } catch (err) {
    const curDelay = state.tries === 0 ? opts.delay : state.delay;
    if (state.tries < opts.maxTries) {
      await new Promise((resolve, reject) => setTimeout(resolve, curDelay))
      await retry(fn, opts, {
        tries: state.tries + 1,
        delay: backoffFns[opts.backoff](curDelay),
        errors: state.errors.concat(err),
      })
    } else {
      opts.logger('Max retries reached', state.errors)
      throw Error('Max retries reached')
    }
  }
}

module.exports = retry