Listening to the YouTube Embed Iframe time change events without polling player.getCurrentTime()

yt.js

// Load the IFrame Player API code asynchronously.
var tag = document.createElement("script");

tag.src = "https://www.youtube.com/iframe_api";
var firstScriptTag = document.getElementsByTagName("script")[0];
firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);

// Instantiate the Player.
function onYouTubeIframeAPIReady() {
  var player = new YT.Player("player", {
    height: "390",
    width: "640",
    videoId: "M7lc1UVf-VE"
  });

  // This is the source "window" that will emit the events.
  var iframeWindow = player.getIframe().contentWindow;
  
  // So we can compare against new updates.
  var lastTimeUpdate = 0;

  // Listen to events triggered by postMessage,
  // this is how different windows in a browser
  // (such as a popup or iFrame) can communicate.
  // See: https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage
  window.addEventListener("message", function(event) {
    // Check that the event was sent from the YouTube IFrame.
    if (event.source === iframeWindow) {
      var data = JSON.parse(event.data);

      // The "infoDelivery" event is used by YT to transmit any
      // kind of information change in the player,
      // such as the current time or a playback quality change.
      if (
        data.event === "infoDelivery" &&
        data.info &&
        data.info.currentTime
      ) {
        // currentTime is emitted very frequently,
        // but we only care about whole second changes.
        var time = Math.floor(data.info.currentTime);

        if (time !== lastTimeUpdate) {
          lastTimeUpdate = time;
          console.log(time); // Update the dom, emit an event, whatever.
        }
      }
    }
  });
}

See this live at: https://codepen.io/zavan/pen/PoGQWmG

Listening to volume/mute changes: https://codepen.io/zavan/pen/yLavMOw

This is awesome dude, using this extensively for my current Spotify clone project that fetches audio from YouTube music videos in a iframe project. Thank you 🙏

Awesome Man! Can we use this event for setting up player properties as well ?