youtubeCheck.js

const checkAvailability = new Promise((resolve) => {
  const image = new Image();
  const loadCB = function() {
    resolve(image.height > 1);
  }
  image.onload = loadCB;
  image.onerror = loadCB;
  image.src = "https://youtube.com/favicon.ico";
});

// Usage:
// checkAvailability().then(isAvailable)
// Or in async/await fashion
// const isAvailable = async checkAvailability();