universal-fetch (aka. the-fetch-you-were-looking-for)

Universal JavaScript fetch utility for NodeJS, Browsers and React-Native*

* React-Native coming soon

About

Using fetch in a Node library that could potentially be used on the web, for instance, is a massive main. Node doesn't have a fetch method and the node-fetch library doesn't play well in the browser due to Buffer support etc.

This library aims to provide pre-build fetch methods for each environment:

• NodeJS (via node-fetch)
• Browser (via window.fetch or GitHub's fetch polyfill)
• React-Native (via global.fetch with Buffer polyfill)

Installation and Support

Install using the following:

npm install the-fetch-you-were-looking-for --save

This library supports NodeJS version 6 and above.

Usage

This library can be used in a variety of different environments, and should be imported like such:

• NodeJS: const fetch = require("the-fetch-you-were-looking-for/node.js");
• Browsers: import fetch from "the-fetch-you-were-looking-for/web";
• React-Native: import fetch from "the-fetch-you-were-looking-for/react-native";

Then use fetch as you would normally, taking into account some limitations (mentioned below).

Limitations

This library isn't a drop-in replacement for fetch, and behaves a bit differently on some environments.

NodeJS limitations

When being used on NodeJS, this library exports node-fetch. node-fetch handles .text() and .json() outputs normally, but does not support .blob(). It is therefore important to mention that .blob() is not supported at all by this library (use .buffer() instead).

Fetching with credentials also behaves differently to the browser implementation, and these differences can be found by reviewing the node-fetch repository.

Web limitations

Currently, this library only exports the browser's fetch method. It does however handle the result and provides the .buffer() response method similarly to the NodeJS implementation.

React-Native limitations

When used in React-Native, this library uses XMLHttpRequest to polyfill fetch. The built-in fetch is very rough around the edges and doesn't function quite like expected. Using an XHR allows this library to return binary data in Buffer form.

The fetch command itself is much simpler, and its options only support the following items:

• method: The method to use for the request
• headers: Key-value store of the headers for the request
• body: The body to send with the request. This supports FormData for uploading files.

It also supports only several response actions:

• .text(): Output text (Promise -> String)
• .json(): Output JS object (Promise -> Object)
• .buffer(): Output Buffer (polyfilled) (Promise -> Buffer)

Testing

Simply run npm t to run the tests.

You can run Node-only tests by using npm run test:node, and web-only by using npm run test:web. You can develop with the web-tests in watch-mode by running npm run test:web:watch.