node.js - How to add campaign tracking data to any url automatically? -

i bunch of different url sources , redirect same url, campaign data added url (to track referred clicks).

for example have these urls:

www.example.com/category/product/name.html

www.example.com/id_product=5

i want add @ end following: utm_source=source&utm_medium=medium&utm_campaign=campaign

and urls become

www.example.com/category/product/name.html?utm_source=source&utm_medium=medium&utm_campaign=campaign

www.example.com/id_product=5&utm_source=source&utm_medium=medium&utm_campaign=campaign

how correctly check , cover cases if url string has parameters, , add mine? want in node.js

thank you

elaborating on @snkashis, similar arguably more elegant solution, again using node's url module, is:

var addqueryparams = function (cleanurl) {   var obj = url.parse(cleanurl, true, false);      obj.query['utm_source'] = 'source';   obj.query['utm_medium'] = 'medium';   obj.query['utm_campaign'] = 'campaign';   delete obj.search; // makes format compose search string out of query object   var trackedurl = url.format(obj);   return trackedurl; }; 

this works, because url.format first looks search and, if can't find it, composes query string query object

(taken node url module documentation http://nodejs.org/api/url.html#url_url_format_urlobj )

• search used in place of query

• query (object; see querystring) used if search absent.