https://lvshuncai.com/js/bookmark.js

1/* global CONFIG */
2
3document.addEventListener('DOMContentLoaded', () => {
4  'use strict';
5
6  const doSaveScroll = () => {
7    localStorage.setItem('bookmark' + location.pathname, window.scrollY);
8  };
9
10  const scrollToMark = () => {
11    let top = localStorage.getItem('bookmark' + location.pathname);
12    top = parseInt(top, 10);
13    // If the page opens with a specific hash, just jump out
14    if (!isNaN(top) && location.hash === '') {
15      // Auto scroll to the position
16      window.anime({
17        targets  : document.scrollingElement,
18        duration : 200,
19        easing   : 'linear',
20        scrollTop: top
21      });
22    }
23  };
24  // Register everything
25  const init = function(trigger) {
26    // Create a link element
27    const link = document.querySelector('.book-mark-link');
28    // Scroll event
29    window.addEventListener('scroll', () => link.classList.toggle('book-mark-link-fixed', window.scrollY === 0), { passive: true });
30    // Register beforeunload event when the trigger is auto
31    if (trigger === 'auto') {
32      // Register beforeunload event
33      window.addEventListener('beforeunload', doSaveScroll);
34      document.addEventListener('pjax:send', doSaveScroll);
35    }
36    // Save the position by clicking the icon
37    link.addEventListener('click', () => {
38      doSaveScroll();
39      window.anime({
40        targets : link,
41        duration: 200,
42        easing  : 'linear',
43        top     : -30,
44        complete: () => {
45          setTimeout(() => {
46            link.style.top = '';
47          }, 400);
48        }
49      });
50    });
51    scrollToMark();
52    document.addEventListener('pjax:success', scrollToMark);
53  };
54
55  init(CONFIG.bookmark.save);
56});