Intro.js main functions to start/stop a tour return a
Promise object. You can also return a
Promise object in the callback functions
onbeforechange) and Intro.js internally waits for that
Promise object to be fulfilled. You can use this concept to perform async I/O (e.g. sending HTTP calls) before moving to the next step of the tour.
In the following example, we are returning a
Promise object and we resolve it after 500ms: