Response.type

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.

The type read-only property of the Response interface contains the type of the response. It can be one of the following:

  • basic: Normal, same origin response, with all headers exposed except “Set-Cookie” and “Set-Cookie2″.
  • cors: Response was received from a valid cross-origin request. Certain headers and the body may be accessed.
  • error: Network error. No useful information describing the error is available. The Response’s status is 0, headers are empty and immutable. This is the type for a Response obtained from Response.error().
  • opaque: Response for “no-cors” request to cross-origin resource. Severely restricted.

Note: An "error" Response never really gets exposed to script: such a response to a fetch() would reject the promise.

Syntax

var myType = response.type;

Value

A ResponseType string indicating the type of the response.

Example

In our Fetch Response example (see Fetch Response live) we create a new Request object using the Request() constructor, passing it a JPG path. We then fetch this request using fetch(), extract a blob from the response using Body.blob, create an object URL out of it using URL.createObjectURL, and display this in an <img>.

Note that at the top of the fetch() block we log the response type to the console.

var myImage = document.querySelector('img');

var myRequest = new Request('flowers.jpg');

fetch(myRequest).then(function(response) {
  console.log(response.type); // returns basic by default
  response.blob().then(function(myBlob) {
    var objectURL = URL.createObjectURL(myBlob);
    myImage.src = objectURL;
  });
});

Specifications

Specification Status Comment
Fetch
The definition of 'type' in that specification.
Living Standard Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 42
41[1]
39 (39)
34[2]
Not supported

29
28[1]

Not supported
Feature Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Phone Opera Mobile Safari Mobile Chrome for Android
Basic support Not supported Not supported Not supported Not supported Not supported Not supported Not supported

[1] The implementation of this feature is behind the "Experimental Web Platform Features" preference in chrome://flags.

[2] The implementation of this feature is behind the preference dom.fetch.enabled in about:config, defaulting to false.

See also

License

© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/response/type