A simple function to build a single campaign identifier (CID) string out of a collection of utm_ parameters.

buildCIDfromUTM.js

/**
 * builds a single campaign identifier (CID) string out of a collection of utm_ parameters
 * payload is required, but all properties of payload are optional
 */
function buildCIDfromUTM(payload) {
  var delimiter = payload.delimiter || '_';
  var cid = payload.cid || [
    payload.medium,
    payload.source,
    payload.campaign,
    payload.term,
    payload.content
  ].join(delimiter);

  // remove any TRAILING delimiters (will return '' if cid contains ONLY delimiters)
  var patt = new RegExp(delimiter + "+$");
  cid = cid.replace(patt, '');

  return cid;
}

// EXAMPLE
var cid = buildCIDfromUTM({
  delimiter: '~',
  cid: '', // ?cid=
  medium: 'ppc', // &utm_medium=
  source: 'google', // &utm_source=
  campaign: 'yougetthegist', // &utm_campaign=
  term: 'hitgovernor', // &utm_term=
  content: '' // &utm_content=
});

console.log(cid);
// result: "ppc~google~yougetthegist~hitgovernor"