a11yist/app/javascript/controllers/toast_controller.js

import { Controller } from "@hotwired/stimulus"
import * as bootstrap from "bootstrap"

// Connects to data-controller="toast"
export default class extends Controller {
  connect() {
    const shownKey = `toastsShown[${this.element.getAttribute("data-ts")}]`
    if(!window.sessionStorage.getItem(shownKey)) {
      window.sessionStorage.setItem(shownKey, Date.now());
      const toastBootstrap = bootstrap.Toast.getOrCreateInstance(this.element)
      toastBootstrap.show()
    }
  }
}