Bookmarklet to scroll through lobste.rs comments in order

lobsters new comments.js

javascript:void(
  (function() {
    this.distanceFromTop = (a, b) => {
      return Math.sign(a.getBoundingClientRect().top - b.getBoundingClientRect().top);
    };

    this.setUnreadElements = () => {
      document.unreadElements = [...document.querySelectorAll('[class*=unread]')].sort(this.distanceFromTop);
    };

    this.parentComment = (el) => {
      return el.closest('.comment');
    };

    this.focusElement = (el) => {
      document.oldBackgroundColor = el.style.backgroundColor;
      el.style.backgroundColor = "#FDFF47";
      el.scrollIntoView({ block: 'center',  behavior: 'smooth' });
    };

    this.unFocusElement = (el) => {
      el.style.backgroundColor = document.oldBackgroundColor;
    };

    if (document.unreadElements === undefined) {
      this.setUnreadElements();
    } else if (document.unreadElements.length == 0) {
      return;
    };

    this.unFocusElement(this.parentComment(document.unreadElements[document.unreadElements.length - 1]));
    this.focusElement(this.parentComment(document.unreadElements[0]));
    document.unreadElements.push(document.unreadElements.shift());

    // Just reverse everything to go backwards:
    // document.unreadElements.unshift(document.unreadElements.pop());
    // this.unFocusElement(this.parentComment(document.unreadElements[0]));
    // this.focusElement(this.parentComment(document.unreadElements[document.unreadElements.length - 1]));

  })()
)