#117 - Page Scroll Progress Bar v0.1

<!-- 💙 MEMBERSCRIPT #117 v0.1 💙 - PAGE SCROLL PROGRESS BAR -->
<script>
  // Function to update the progress bar
  function updateProgressBar() {
    const container = document.querySelector('[ms-code-ps="container"]');
    const bar = document.querySelector('[ms-code-ps="bar"]');
    const startElement = document.querySelector('[ms-code-ps="start"]');
    const endElement = document.querySelector('[ms-code-ps="end"]');

    if (!container || !bar) return;

    const windowHeight = window.innerHeight;
    const documentHeight = document.documentElement.scrollHeight;
    const scrollTop = window.pageYOffset || document.documentElement.scrollTop;

    let startPosition = 0;
    let endPosition = documentHeight - windowHeight;

    if (startElement) {
      const startRect = startElement.getBoundingClientRect();
      startPosition = scrollTop + startRect.top - windowHeight;
    }

    if (endElement) {
      const endRect = endElement.getBoundingClientRect();
      endPosition = scrollTop + endRect.top - windowHeight;
    }

    const scrollRange = endPosition - startPosition;
    const scrollProgress = scrollTop - startPosition;
    const scrollPercentage = Math.max(0, Math.min(100, (scrollProgress / scrollRange) * 100));

    // Use requestAnimationFrame for smooth animation
    requestAnimationFrame(() => {
      bar.style.width = `${scrollPercentage}%`;
      bar.style.transition = 'width 0.1s linear';
    });
  }

  // Throttle function to limit how often updateProgressBar is called
  function throttle(func, limit) {
    let inThrottle;
    return function() {
      const args = arguments;
      const context = this;
      if (!inThrottle) {
        func.apply(context, args);
        inThrottle = true;
        setTimeout(() => inThrottle = false, limit);
      }
    };
  }

  // Add scroll event listener with throttling
  window.addEventListener('scroll', throttle(updateProgressBar, 10));

  // Initial call to set the correct width on page load
  updateProgressBar();
</script>