Headers.keys()

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 Headers.keys() method returns an iterator allowing to go through all keys contained in this object. The keys are ByteString objects.

Note: This method is available in Web Workers.

Syntax

JavaScript
headers.keys();

Return value

Returns an iterator.

Example

js;highlight:[7]
// Create a test Headers object
var myHeaders = new Headers();
myHeaders.append('Content-Type', 'text/xml');
myHeaders.append('Vary', 'Accept-Language');

// Display the keys
for(var key of myHeaders.keys()) {
   console.log(key); 
}

The result is:

JavaScript
content-type
vary

Specifications

Specification Status Comment
Fetch
The definition of 'Headers.keys() (as iterator<>)' in that specification.		 Living Standard Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support ? 44 (44) ? ? ?
Feature Android Chrome for Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? 44.0 (44) (Yes) ? ? ?

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/headers/keys

API Experimental Fetch API Headers Method Reference