srcset 
Parse and stringify the HTML
<img>srcset attribute.
Useful if you're creating a polyfill, build-tool, etc.
Install
$ npm install --save srcset
Usage
How an image with srcset might look like:
<img alt="The Breakfast Combo"
src="banner.jpg"
srcset="banner-HD.jpg 2x, banner-phone.jpg 100w, banner-phone-HD.jpg 100w 2x">
Then have some fun with it:
var srcset = require('srcset');
var parsed = srcset.parse('banner-HD.jpg 2x, banner-phone.jpg 100w');
console.log(parsed);
/*
[
{ url: 'banner-HD.jpg', density: 2 },
{ url: 'banner-phone.jpg', width: 100 }
]
*/
parsed.push({ url: 'banner-phone-HD.jpg', width: 100, density: 2 });
var stringified = srcset.stringify(parsed);
console.log(stringified);
/*
banner-HD.jpg 2x, banner-phone.jpg 100w, banner-phone-HD.jpg 100w 2x
*/
API
.parse()
Accepts a srcset string and returns an array of objects with the possible properties: url (always), width, height, density.
.stringify()
Accepts an array of objects with the possible properties: url (required), width, height, density and returns a srcset string.
License
MIT © Sindre Sorhus