<nav class="navbar navbar-expand-md navbar-dark bg-dark">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">
      <img class="logo horizontal-logo" src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/162656/horizontal-logo.svg" alt="forecastr logo">
	  </a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarSupportedContent">
      <ul class="navbar-nav ml-auto">
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item dropdown">
          <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown2" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown
          </a>
          <div class="dropdown-menu" aria-labelledby="navbarDropdown2">
            <a class="dropdown-item" href="#">Action</a>
            <a class="dropdown-item" href="#">Another action</a>
            <div class="dropdown-divider"></div>
            <a class="dropdown-item" href="#">Something else here</a>
          </div>
        </li>
        <li class="nav-item dropdown">
          <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown3" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown
          </a>
          <div class="dropdown-menu" aria-labelledby="navbarDropdown3">
            <a class="dropdown-item" href="#">Action</a>
            <a class="dropdown-item" href="#">Another action</a>
            <div class="dropdown-divider"></div>
            <a class="dropdown-item" href="#">Something else here</a>
          </div>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">Link</a>
        </li>
      </ul>
    </div>
  </div>
</navbar>
body {
  background: #f2f2f2;
}

.navbar .nav-item:not(:last-child) {
  margin-right: 35px;
}

.dropdown-toggle::after {
   transition: transform 0.15s linear; 
}

.show.dropdown .dropdown-toggle::after {
  transform: translateY(3px);
}

.dropdown-menu {
  margin-top: 0;
}
const $dropdown = $(".dropdown");
const $dropdownToggle = $(".dropdown-toggle");
const $dropdownMenu = $(".dropdown-menu");
const showClass = "show";

$(window).on("load resize", function() {
  if (this.matchMedia("(min-width: 768px)").matches) {
    $dropdown.hover(
      function() {
        const $this = $(this);
        $this.addClass(showClass);
        $this.find($dropdownToggle).attr("aria-expanded", "true");
        $this.find($dropdownMenu).addClass(showClass);
      },
      function() {
        const $this = $(this);
        $this.removeClass(showClass);
        $this.find($dropdownToggle).attr("aria-expanded", "false");
        $this.find($dropdownMenu).removeClass(showClass);
      }
    );
  } else {
    $dropdown.off("mouseenter mouseleave");
  }
});

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js
  2. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.3.1/js/bootstrap.min.js