@grund/fetch

The purpose of this package is twofolded:

1. Create a common interface for other grund packages to use.
2. Intercept and throw enhanced errors (from @grund/errors)

Error intercepting

Using the fetch API can be a bit tricky and hard to understand - especially in the context of errors. So we created this wrapper around the fetch function which acts in exactly the same way as a normal fetch does - but throws a set of enhanced errors (from @grund/errors). These errors are the following:

• ConnectionError - If the native fetch function throws an error and the user is not connected to the internet (using the package is-online).
• ServerUnavailableError - If the native fetch function throws an error and the user is online, indicating that the server is unavailable in some way.
• BadRequestError - The fetch got a result on the request, but the status code was 400.
• AuthenticationError - The status was 401.
• ForbiddenError - The status was 403.
• UrlNotFoundError - The status was 404.

401 status

The http error with code 401 has the name Unauthorized which essentially means the same as the name for 403 - Forbidden.

Quick recap:

• authentication - Find out if you are who you say you are.
• authorization - I know who you are, but are you allowed to do what you want do to?

According to https://stackoverflow.com/questions/3297048/403-forbidden-vs-401-unauthorized-http-responses, the name Unauthorized is a but unfortunate since what it means in practise in that you aren't authenticated. This is why this package throws an AuthenticationError when it receives the code 401.

Native fetch

fetch is built into all modern web browsers, but not in NodeJS. So when we want to use this package in a node environment we need to tell it to use a specific fetch instance.

To fix this the package exposes setNativeFetch. So in you initiation module in your application, make sure to set your native fetch instance with this function. Examples:

// NodeJS

import fetch from 'node-fetch';

import { setNativeFetch } from '@grund/fetch';

setNativeFetch(fetch);

// Browser

import { setNativeFetch } from '@grund/fetch';

setNativeFetch(window.fetch);