The Crawler method, renderJavascript can be used for extracting data from JS web apps - https://www.algolia.com/doc/tools/crawler/extracting-data/overview/#extract-from-javascript-based-sites
This method isn't available on Build Plan applications. If you're on a Build Plan application, and you need to use this method, you'll need to upgrade to one of our paid plans (e.g. Grow).