The goal is to add some extra functionality to node-fetch in a non-intrusive way:

• Extra options:
  • type FetchResource: Parameters<fetch>[0]
  • type FetchState: {retryCount: number, fetchId: string, resource: FetchResource, options: FetchOptions}
  • type FetchStats: {ok, error, totalMs, sentMs, receivedMs, sent, received}
  • retry: number | ({error: Error, response: Response, state: FetchState}) => Promise<boolean | {resource: FetchResource, options: FetchOptions} (could just return state)>
    • number is just an easy option to retry with a given number of attempts
    • and function is an interface in which you can make complex rules whether to retry or not
      • returning true = retry
      • returning falsy = don't retry, fetch will throw the original error
      • returning object = retry with given parameters (allows you to modify request on retry)
      • throwing = don't retry, fetch will throw what you've thrown
  • validate: true | (response: Omit<Response, "body">, state: FetchState) => Promise<void>: throws allows to retry the request (with no body consumed yet!) on particular circumstances
    • if true, then validate: res => if (!res.ok ) throw HttpError
  • validate.json, validate.buffer, etc - same rule as validate, but with access to the parsed body (result: any, state: FetchState)
  • timeout: number: default value for all the request handling (doing the request + fetching the body); same as in node-fetch v2
  • requestTimeout = timeout for await fetch(...) (includes body upload time)
  • bodyTimeout = timeout for fetching the whole body, i.e. await res.json()
  • stallTimeout = same as body, except instead of fixed time of fetching the whole body, we count the time of download speed of 0 bytes/s
• todo: abort controller we use for timeout handling shouldn't ignore abort controller given in the options (already put the comment in the code)
• todo: noProgress but for file upload (request)?
• Extra Response fields:
  • completed: Promise<FetchStats>: Promise for body completion - rejects if fetch body or validation failed
• makeFetch with built-in async-sema options like Sema and RateLimit
• rich logging: ?
  • request start (include the body if it's string)
  • request done/failed
  • download for larger bodies (maybe with download speed?)
  • retries
  • sema
• tests
• todo: download helper that will hash on fly and have retry support

Helper StatsStream: maybe exists somewhere? re-export or rebuild