in js/libs/ical.js [169:180]
var categoriesParam = function (name) {
var separatorPattern = /\s*,\s*/g;
return function (val, params, curr) {
storeParam(val, params, curr)
if (curr[name] === undefined)
curr[name] = val ? val.split(separatorPattern) : []
else
if (val)
curr[name] = curr[name].concat(val.split(separatorPattern))
return curr
}
}