cross-fetch
[](https://travis-ci.org/lquixada/cross-fetch)
[](https://saucelabs.com/u/cross-fetch)
[](https://codecov.io/gh/lquixada/cross-fetch)
[](https://david-dm.org/lquixada/cross-fetch)
[](https://www.npmjs.com/package/cross-fetch)
[](https://opensource.org/licenses/MIT)
================
Universal WHATWG Fetch API for Node, Browsers and React Native. The scenario that cross-fetch really shines is when the same javascript codebase needs to run on different platforms.
- **Platform agnostic**: browsers, node or react native
- **Optional polyfill**: it's up to you if something is going to be added to the global object or not
- **Simple interface**: no instantiation, no configuration and no extra dependency
- **WHATWG compliant**: it works the same way wherever your code runs
- **Updated**: lastest version of whatwg-fetch and node-fetch used
* * *
## Table of Contents
- [Install](#install)
- [Usage](#usage)
- [Demo & API](#demo--api)
- [FAQ](#faq)
- [Supported environments](#supported-environments)
- [Thanks](#thanks)
- [License](#license)
- [Author](#author)
- [Sponsors](#sponsors)
* * *
## Install
```sh
npm install --save cross-fetch
```
As a [ponyfill](https://github.com/sindresorhus/ponyfill):
```javascript
// Using ES6 modules with Babel or TypeScript
import fetch from 'cross-fetch';
// Using CommonJS modules
const fetch = require('cross-fetch');
```
As a polyfill:
```javascript
// Using ES6 modules
import 'cross-fetch/polyfill';
// Using CommonJS modules
require('cross-fetch/polyfill');
```
The CDN build is also available on unpkg:
```html
```
This adds the fetch function to the window object. Note that this is not UMD compatible.
* * *
## Usage
With [promises](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise):
```javascript
import fetch from 'cross-fetch';
// Or just: import 'cross-fetch/polyfill';
fetch('//api.github.com/users/lquixada')
.then(res => {
if (res.status >= 400) {
throw new Error("Bad response from server");
}
return res.json();
})
.then(user => {
console.log(user);
})
.catch(err => {
console.error(err);
});
```
With [async/await](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function):
```javascript
import fetch from 'cross-fetch';
// Or just: import 'cross-fetch/polyfill';
(async () => {
try {
const res = await fetch('//api.github.com/users/lquixada');
if (res.status >= 400) {
throw new Error("Bad response from server");
}
const user = await res.json();
console.log(user);
} catch (err) {
console.error(err);
}
})();
```
> ⚠️ **Warning**: If you're in an environment that doesn't support Promises such as Internet Explorer, you must install an ES6 Promise compatible polyfill. [es6-promise](https://github.com/jakearchibald/es6-promise) is suggested.
## Demo & API
You can find a comprehensive doc at [Github's fetch](https://github.github.io/fetch/) page. If you want to play with cross-fetch, these resources can be useful:
* [**JSFiddle playground**](https://jsfiddle.net/lquixada/3ypqgacp/) ➡️
* [**Public test suite**](https://lquixada.github.io/cross-fetch/test/saucelabs/) ➡️
> **Tip**: Run theses resources on various browsers and with different settings (for instance: cross-domain requests, wrong urls or text requests). Don't forget to open the console in the test suite page and play around.
## FAQ
#### Yet another fetch library?
I did a lot of research in order to find a fetch library that could be simple, cross-platorm and provide polyfill as an option. There's a plethora of libs out there but none could match those requirements.
#### Why not isomorphic-fetch?
My preferred library used to be [isomorphic-fetch](https://github.com/matthew-andrews/isomorphic-fetch) but it has this [bug](https://github.com/matthew-andrews/isomorphic-fetch/issues/125) that prevents it from running in a react native environment. It seems it will never be fixed since the author hasn't been commiting for more than a year. That means dependencies are outdated as well.
#### Why polyfill might not be a good idea?
In a word? Risk. If the spec changes in the future, it might be problematic to debug. Read more about it on [sindresorhus's ponyfill](https://github.com/sindresorhus/ponyfill#how-are-ponyfills-better-than-polyfills) page. It's up to you if you're fine with it or not.
#### How does cross-fetch work?
Just like isomorphic-fetch, it is just a proxy. If you're in node, it delivers you the [node-fetch](https://www.npmjs.com/package/node-fetch) library, if you're in a browser or React Native, it delivers you the github's [whatwg-fetch](https://github.com/github/fetch/). The same strategy applies whether you're using polyfill or ponyfill.
## Who's Using It?
* [VulcanJS](http://vulcanjs.org)
* [graphql-request](https://github.com/graphcool/graphql-request)
* [Swagger](https://swagger.io/)
## Supported environments
* Node 6+
* React-Native
[](https://saucelabs.com/u/cross-fetch)
## Thanks
Heavily inspired by the works of [matthew-andrews](https://github.com/matthew-andrews). Kudos to him!
## License
cross-fetch is licensed under the [MIT license](https://github.com/lquixada/cross-fetch/blob/master/LICENSE) © [Leonardo Quixadá](https://twitter.com/lquixada/)
## Author
|[](https://github.com/lquixada)|
|:---:|
|[@lquixada](http://www.github.com/lquixada)|
## Sponsors
Manual cross-browser testing is provided by the following sponsor:
[](https://www.browserstack.com/)