Javascript 回调未按正确顺序触发

Question

我正在使用 jQuery、skrollr 和 skrollr-menu 来创建特定的导航动画。我想要的动画如下：

1. 用户点击链接
2. 黑色 div 淡出页面
3. 页面滚动到下方的位置
4. 黑色 div 淡出并离开页面

您可以在http://www.gramercyparkhotel.com/ 看到该动画的示例。看起来很简单；但是，随着<div> 的淡入，在动画结束之前触发滚动，导致在屏幕变黑之前滚动内容闪烁。这不应该发生，因为一切都是使用回调来计时的，所以如果动画还没有完成，为什么会调用带有滚动的后续函数？

编辑

我在下面添加了一个coden-p。看起来好像在动画完成之前调用了 animateTo 调用。 animateTo 滚动到顶部，然后滚动到正确的位置。如果回调实际发挥应有的作用，我不关心这种行为。

$(document).ready( function() {
  // Initialize skrollr
  var s = skrollr.init({
    keyframe: function(element, name, direction) {
      $(element).trigger(name, [direction]);
    }
  });

  function hideFader($fader, callback) {
    var callback = callback || function() { return false; };
    $fader.animate({
      'opacity': 0
    }, 500, function() {
      $fader.css('top', '-100%');
      callback();
    });
  }

  function showFader($fader, callback) {
    var callback = callback || function() { return false; };
    $fader.css('top', '0%');

    $fader.animate({
      'opacity': 1
    }, 500, callback);
  }

  var $fader = $('#fader');
  hideFader($fader);

  skrollr.menu.init(s, {
    animate: false,
    handleLink: function(link) {
      showFader($fader, function() {
        var $location = $($(link).attr('href')),
            menuTop;

        if($(link).attr('href') === '#home') {
          menuTop = 0;
        } else {
          menuTop = Math.round(parseInt($location.attr('data-dtcp')) / 100 * $('#home').height());
        }

        s.animateTo(menuTop, {
          duration: 0,
          done: function() {
            hideFader($fader);
          }
        });
      });
    },
    complexLinks: false,
    updateUrl: false
  });
});

.navigation-centered {
  position: fixed;
  bottom: 0;
  width: 100%;
  background-color: #171511;
  background-color: rgba(23, 21, 17, 0.9);
  z-index: 1000;
}
.navigation-centered .navigation-centered-wrapper {
  position: relative;
  border: 10px solid transparent;
  padding: 15px 0;
  min-width: 100%;
}
.navigation-centered ul.navigation-centered-menu {
  clear: both;
  display: none;
  margin: 0 auto;
  overflow: visible;
  padding: 0;
  width: 100%;
  display: block;
  text-align: center;
}
.navigation-centered ul.navigation-centered-menu.show {
  display: block;
}
.navigation-centered ul li.nav-link {
  display: block;
  text-align: right;
  width: 100%;
  display: inline;
}
.navigation-centered ul li.nav-link a {
  display: inline-block;
  color: #b5b4b2;
  text-decoration: none;
  outline: none;
}
.navigation-centered ul li.nav-link a:hover, .navigation-centered ul li.nav-link a:active, .navigation-centered ul li.nav-link a:visited, .navigation-centered ul li.nav-link a:focus {
  color: #b5b4b2;
  text-decoration: none;
  outline: none;
}
.navigation-centered ul li.nav-link:after {
  content: '\00B7';
  padding-right: 1em;
  display: inline-block;
  color: #b5b4b2;
}
.navigation-centered ul li.nav-link:last-child:after {
  content: '';
  display: none;
}
.navigation-centered ul li.nav-link a {
  padding-right: 1em;
}

.fullscreen, #fader {
  height: 100%;
  width: 100%;
  height: 100vh;
  width: 100vw;
}

#home {
  background-color: red;
}

#about {
  background-color: blue;
}

#gallery {
  background-color: green;
}

#contact {
  background-color: yellow;
}

#blog {
  background-color: purple;
}

#fader {
  position: fixed;
  z-index: 10000;
  background: #000;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://sid.artlyticalmedia.com/wp-content/themes/sanctuariesinteriordesign/bower_components/skrollr/dist/skrollr.min.js"></script>
<script src="http://sid.artlyticalmedia.com/wp-content/themes/sanctuariesinteriordesign/bower_components/skrollr-menu/dist/skrollr.menu.min.js"></script>

<div id="home" class="fullscreen"
  data-dtcp="0"
  data-0p="top: 0%;"
  data-100p="top: -100%;">
  <h1>home</h1>
</div>

<div id="gallery" class="fullscreen"
  data-dtcp="100"
  data-100p="top: 100%;"
  data-200p="top: 0%;"
  data-300p="top: -100%;">
  <h1>gallery</h1>
</div>

<div id="about" class="fullscreen"
  data-dtcp="200"
  data-200p="top: 100%;"
  data-300p="top: 0%;"
  data-400p="top: -100%;">
  <h1>about</h1>
</div>

<div id="blog" class="fullscreen"
  data-dtcp="400"
  data-300p="top: 100%;"
  data-400p="top: 0%;"
  data-500p="top: -100%;">
  <h1>blog</h1>
</div>

<div id="contact" class="fullscreen"
  data-dtcp="500"
  data-400p="top: 100%;"
  data-500p="top: 0%;"
  data-600p="top: -100%;">
  <h1>contact</h1>
</div>

<div id="fader"></div>

<footer id="footer">
  <nav id="nav-main" class="nav-main" role="navigation">
    <div class="navigation-centered" role="banner">
      <div class="navigation-centered-wrapper">
        <nav role="navigation">
          <ul id="js-navigation-centered-menu" class="navigation-centered-menu show">
            <li class="nav-link">
              <a href="#home">home</a>
            </li>
            <li class="nav-link">
              <a href="#gallery">gallery</a>
            </li>
            <li class="nav-link">
              <a href="#about">about</a>
            </li>
            <li class="nav-link">
              <a href="#blog">blog</a>
            </li>
            <li class="nav-link">
              <a href="#contact">contact</a>
            </li>
          </ul>
        </nav>
      </div>
    </div>
  </nav><!-- #nav -->
</footer>

Answer 1

问题是在handleLink 函数中没有返回任何值，skrollr-menu 默认会滚动到 0。我通过在函数末尾添加return null; 来修复它。