How to run javascript in a flow?

Hi,

A question that might have a rather simple answer, but I’m using a theme that has Toast built-in, and rather than using Wapplers integration, I want to use the themes since it’s slightly customized and already themed.

Running the following in a browser console works:

Command: toastr["error"]("Your username or password was incorrect.", "Invalid Login!")

toastr.options = {
  "closeButton": false,
  "debug": false,
  "newestOnTop": false,
  "progressBar": false,
  "positionClass": "toast-top-full-width",
  "preventDuplicates": false,
  "onclick": null,
  "showDuration": 300,
  "hideDuration": 1500,
  "timeOut": 5000,
  "extendedTimeOut": 1000,
  "showEasing": "swing",
  "hideEasing": "linear",
  "showMethod": "fadeIn",
  "hideMethod": "fadeOut"
}

I essentially want to perform this when someone enters the incorrect username/password on the login screen. The easiest way to do this seems to be to run a dynamic event on unauthorized, which then runs a flow. However, how would I send the above command via the flow? “Run JavaScript” exists, but I’m not exactly sure how I would format the above to go into this.