A simple trick to check is a video existing or not

youtube.js

// definition

function videoExists(url) {
  var exists;
  var video;
  try {
    video = new URL(url);
  } catch {
    throw new Error("Invalid URL 😳")
  }
  var img = new Image();
  img.src = "https://img.youtube.com/vi/" + video.searchParams.get('v') + "/mqdefault.jpg";
  img.onload = function () {
    exists = !this.width === 120 && !this.height === 90;
  }
  img.onerror = function () {
    throw new Error("Hmm... Something went wrong :(");
  }
  return exists;
}

// usage

videoExists("https://www.youtube.com/watch?v=notExisting") // returns false
videoExists("https://www.youtube.com/watch?v=--AuxdQUdlo") // returns true

// advanced usage

if (videoExists("YOUR VIDEO")) {
  console.log("This video exists")
} else {
  console.log("I can't found this video :(")
}

// credits

/*
* Credits to YouTube and GitHub
**/

// note

/*
* This code is free to use
**/

I hope I can help you with your program or anything else :)