url-params 
Utility functions for adding, removing and setting values in url query strings. This is particularly suited to dealing with multi-value, '+' separated query strings.
Installation
If you don't have Yeoman installed yet, run the following.
npm install url-params
Usage
var urlParams = require('urlParams');
var oldUrl = 'http://www.example.com/?foo=2+3+6&baz=6';
newUrl = urlParams.add(oldUrl, 'foo', 4);
newUrl = urlParams.add(oldUrl, 'foo', [4, 5]);
newUrl = urlParams.add(oldUrl, 'foo');
newUrl = urlParams.add(http:
newUrl = urlParams.remove(oldUrl, 'foo', 3)
newUrl = urlParams.remove(oldUrl, 'foo', [3, 6])
newUrl = urlParams.remove(oldUrl, 'foo')
newUrl = urlParams.set(oldUrl, 'foo', 3)
newUrl = urlParams.set(oldUrl, 'foo', [3, 6])
newUrl = urlParams.set(oldUrl, 'foo')
License
MIT