Would you create rex or regex to extract a string and create a new field?

I have the raw data below. How do I get the strings after the "action": and put all the results into a new field? {"dateTime":"2018-03-19T05:57:46.3002859Z","ID":"b3f7","account":"9002",xd":"859","action":"Exit"} {"dateTime":"2018-03-19T05:57:47.1102859Z","ID":"cbbf","account":"f295",xd":"f89","tile":"HeroTile","action":"page:http://first.com/roomV8.2/front.main/"} {"dateTime":"2018-03-19T05:57:46.3002859Z","ID":"b3f7","account":"9002",xd":"859","action":"Exit"} {"dateTime":"2018-03-19T05:57:47.1102859Z","ID":"cbbf","account":"f295",xd":"f89","tile":"HeroTile","action":"page:http://second.com/roomV8.2/front.main/"}