In addition to copying the event, this applet uses filter code to calculate the duration of a Google event in minutes so that the value can be passed to an iOS calendar. Here is a copy of the filter code:
https://ifttt.com/applets/YyFJTBuC
Due to limitations in IFTTT's Google and iOS Calendar services, this applet cannot (1) determine when an event is a repeating event or (2) set the all-day flag in the iOS calendar (a Google all-day event is added as a 24-hour event in iOS).
Popular services on IFTTT