Function keydown

scripts/smoothScroll.js:495–592

* Keydown event handler. * @param {Object} event

(event)

   * @param {Object} event
   */
  function keydown(event) {
    let target = event.target;
    let modifier =
      event.ctrlKey ||
      event.altKey ||
      event.metaKey ||
      (event.shiftKey && event.keyCode !== key.spacebar);
    // our own tracked active element could've been removed from the DOM
    if (!document.contains(activeElement)) {
      activeElement = document.activeElement;
    }
    // do nothing if user is editing text
    // or using a modifier key (except shift)
    // or in a dropdown
    // or inside interactive elements
    let inputNodeNames = /^(textarea|select|embed|object)$/i;
    let buttonTypes = /^(button|submit|radio|checkbox|file|color|image)$/i;
    if (
      event.defaultPrevented ||
      inputNodeNames.test(target.nodeName) ||
      (isNodeName(target, "input") && !buttonTypes.test(target.type)) ||
      isNodeName(activeElement, "video") ||
      isInsideYoutubeVideo(event) ||
      target.isContentEditable ||
      modifier
    ) {
      return true;
    }
    // [spacebar] should trigger button press, leave it alone
    if (
      (isNodeName(target, "button") ||
        (isNodeName(target, "input") && buttonTypes.test(target.type))) &&
      event.keyCode === key.spacebar
    ) {
      return true;
    }
    // [arrwow keys] on radio buttons should be left alone
    if (
      isNodeName(target, "input") &&
      target.type == "radio" &&
      arrowKeys[event.keyCode]
    ) {
      return true;
    }
    let xOnly = event.keyCode == key.left || event.keyCode == key.right;
    let overflowing = overflowingAncestor(activeElement, xOnly);
    if (!overflowing) {
      // iframes seem to eat key events, which we need to propagate up
      // if the iframe has nothing overflowing to scroll
      return isFrame ? parent.keydown(event) : true;
    }
    let clientHeight = overflowing.clientHeight;
    let shift,
      x = 0,
      y = 0;
    if (overflowing == document.body) {
      clientHeight = window.innerHeight;
    }