window.fetch polyfill
This fork supports IE8 with es5-shim, es5-sham and es6-promise.
If you also use JSONP, checkout fetch-jsonp.
Fetch API is still very new and not fully supported in some browsers, so you may
need to check browser verson as well as if window.fetch
exists. In this case,
you can set window.__disableNativeFetch = true
to use AJAX polyfill always.
The global fetch
function is an easier way to make web requests and handle
responses than using an XMLHttpRequest. This polyfill is written as closely as
possible to the standard Fetch specification at https://fetch.spec.whatwg.org.
Installation
$ npm install fetch-ie8 --save
You'll also need a Promise polyfill for older browsers.
$ npm install es6-promise
Run this to polyfill the global environment at the beginning of your application.
;
(For a node.js implementation, try node-fetch)
Usage
The fetch
function supports any HTTP method. We'll focus on GET and POST
example requests.
HTML
JSON
Response metadata
Post form
var form = document
Post JSON
File upload
var input = document var form = formform
Success and error handlers
This causes fetch
to behave like jQuery's $.ajax
by rejecting the Promise
on HTTP failure status codes like 404, 500, etc. The response Promise
is
resolved only on successful, 200 level, status codes.
{ if responsestatus >= 200 && responsestatus < 300 return response throw responsestatusText} { return response}
Response URL caveat
The Response
object has a URL attribute for the final responded resource.
Usually this is the same as the Request
url, but in the case of a redirect,
its all transparent. Newer versions of XHR include a responseURL
attribute
that returns this value. But not every browser supports this. The compromise
requires setting a special server side header to tell the browser what URL it
just requested (yeah, I know browsers).
response.headers['X-Request-URL'] = request.url
If you want response.url
to be reliable, you'll want to set this header. The
day that you ditch this polyfill and use native fetch only, you can remove the
header hack.
Browser Support
Latest ✔ | Latest ✔ | 8+ ✔ | Latest ✔ | 6.1+ ✔ |