Replace Rails 5 alert dialog

msgbox.js

promiseBasedConfirmPopup = new Promise((resolve) => {
  // Show a nice popup and resolve to true/false
  setTimeout(() => resolve(true), 2000)
})


$("a[data-confirm]").on("confirm", function(evt) {
  
  // evt.target hold the clicked anchor from where
  // can be extracted some data to build the popup    
  promiseBasedConfirmPopup().then((res) => {
    if (res) {
      // execute default handler if promise resolve true
      // https://github.com/rails/rails/blob/v5.1.4/actionview/app/assets/javascripts/rails-ujs/features/method.coffee
      Rails.handleMethod.apply(evt.target, [evt])
    }
  })

  // this is key, return false to disable default confirm dialog
  // https://github.com/rails/rails/blob/v5.1.4/actionview/app/assets/javascripts/rails-ujs/features/confirm.coffee#L22
  return false
})