UTM-Extractor
This script is used to process events in order to extract and add the utm_source, utm_medium, utm_campaign, utm_content and utm_term properties from the current_url, $current_url, signUpPageConversion, signUpPageLanding, firstPageViewed properties of an event.
The script exports a single function, processEvent(event, { config }), which takes in two arguments:
event: the event object that needs to be processed
config: an object containing any configuration options that may be required by the script
The processEvent() function first checks if the event object has a properties field, and if it does, it iterates through the urlProperties array, checking if the event object has any of the properties in the array that includes the string 'utm'. If it does, it then iterates through the utmProperties array, and uses extractUtmFromUrl(urlString, utm) to extract the value of the utm properties from the URL. If the value is not empty, it adds the extracted value to the event object's properties field.
The extractUtmFromUrl(urlString, utm) function takes the urlString and utm as input and it uses the URL class from the built-in url module to create a new URL object, and uses the searchParams.get(utm) method to get the value of the utm parameter from the url.
Finally, the processed event object is returned by the processEvent() function, to be ingested by the system that called it.
The extracted URL utm properties are then add to the event object, before they are ingested into a data pipeline your analytics platform. This is useful for tracking the source of the user's visit to the website.