首先，你的示例是一个痛苦的阅读，特别是你的JS文件。就这样了
现在，我不知道为什么你有这么多行代码只是切换一个菜单。你需要的是一些CSS和一点JavaScript来切换类。如果是我的话，就这样吧。
所以，这里有一个小东西从我的CodePen来帮助说明我的观点。你可以只修改文件和使用它的菜单

$('a.drop').click(function(e) {
  e.preventDefault();
  $(this).next().toggleClass('active');
});

$('.toggle').click(function(e) {
  e.preventDefault();
  $('nav > .menu').toggle();
  $(this).html(($(this).html() == 'x' ? '☰' : 'x'));
});

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
nav {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background-color: rgba(255,255,255,.8);
}
h5 {padding: 8px;}
nav > .menu {
  display: none;
  position: absolute;
  top: 100%; left: 0; right: 0;
  width: 100%;
  max-height: 400px;
  background-color: rgba(255,255,255,.8)
}
ul {
  list-style: none;
  padding-left: 12px;
}
.toggle {display: block}
a {text-decoration: none;}
li a:hover {
  background-color: rgba(0,0,0,.1);
}
.links {white-space: nowrap;}
a {
  display: block;
  position: relative;
  padding: 8px 12px;
}
a.drop {
  padding-right: 24px;
}
a.drop:after {
  content: '';
  position: absolute;
  top: 50%; right: 8px;
  transform: translateY(-75%) rotate(45deg);
  width: 5px; height: 5px;
  border: 2px solid #444;
  border-color: transparent #444 #444 transparent;
}
.menu .menu, ul.menu .list {
  display: none;
}
.menu .menu.active, ul.menu .list.active, .menu.active > .list {
  display: block;
}

@media screen and (min-width: 768px) {
  .toggle {display: none}
  nav > .menu {
    width: 90%;
    display: flex;
    position: relative;
    justify-content: center;
  }
  nav > ul > li > a {
    padding: 32px!important;
  }
  li:hover > .list, li:hover > .menu {
    border-top: 2px solid #333;
    display: block;
    position: absolute;
    top: 100%; left: 0;
    width: 100%;
    z-index: 1;
  }
  li:hover .menu > .list {
    display: inline-block;
  }
  li:hover .menu a {
    max-width: 120px;
  }
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<nav>
  <a href="#" class="logo"><img src="https://picsum.photos/seed/picsum/60" alt=""></a>
  <ul class="menu">
    <li><a href="#">Link 1</a></li>
    <li>
      <a href="#" class="drop">Menu 1</a>
      <ul class="list">
        <li><a href="#">Sub Link 1</a></li>
        <li><a href="#">Sub Link 2</a></li>
      </ul>
    </li>
    <li>
      <a href="#" class="drop">Menu 2</a>
      <div class="menu">
        <ul class="list">
          <li><h5>Sub Header 1</h5></li>
          <li><a href="#">Sub Link 3</a></li>
          <li><a href="#">Sub Link 4</a></li>
        </ul>  
        <ul class="list">
          <li><h5>Sub Header 2</h5></li>
          <li><a href="#">Sub Link 3</a></li>
          <li><a href="#">Sub Link 4</a></li>
        </ul>
      </div>
    </li>
    <li><a href="#">Link 2</a></li>
  </ul>
  <div class="links">F T G I S &nbsp;</div>
  <a href="#" class="toggle">&#x2630;</a>
</nav>