legendary-doc-site/apps/app/assets/js/live.js

import { Socket } from "phoenix";
import { LiveSocket } from "phoenix_live_view";
import topbar from "topbar";

let csrfToken = document
  .querySelector("meta[name='csrf-token']")
  .getAttribute("content");

let liveSocket = new LiveSocket("/live", Socket, {
  params: { _csrf_token: csrfToken },
});

// Show progress bar on live navigation and form submits
topbar.config({
  barColors: { 0: "#3B82F6" },
  shadowColor: "rgba(0, 0, 0, .3)",
});
window.addEventListener("phx:page-loading-start", (info) => topbar.show());
window.addEventListener("phx:page-loading-stop", (info) => topbar.hide());

// Connect if there are any LiveViews on the page
liveSocket.connect();

// Expose liveSocket on window for web console debug logs and latency simulation:
// >> liveSocket.enableDebug()
// >> liveSocket.enableLatencySim(1000)
// The latency simulator is enabled for the duration of the browser session.
// Call disableLatencySim() to disable:
// >> liveSocket.disableLatencySim()
window.liveSocket = liveSocket;