Multi-Level NavBar in Angular 6 Bootstrap 4

Question

(UPDATE: Resolved - i had to add the javascript in $(document).ready(function(), which i was missing. The below eg worked perfect for me.)

I am trying to make a Multi-Level Navbar work with Angular 6 & Bootstrap 4.

How do i expand and colapse sub-menu's on click or hover? I want the menu to expand to the right...

Eg: I found a solution on this link - but i am not sure how to inject Javascript in a Angular component. https://codepen.io/surjithctly/pen/PJqKzQ

Here are my version details

+-- bootstrap@4.1.3

+-- jquery@3.3.1

+-- popper.js@1.14.4

Below is my Navbar Code

<nav class="navbar navbar-expand-lg navbar-dark">
    <a class="navbar-brand" href="#" style="color: red;">      
      My NAVBAR
    </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 mr-auto">
        <li class="nav-item">
          <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
        </li>        
            <li class="nav-item dropdown">
                <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownHI" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                  Menu
                </a>
                <ul class="dropdown-menu" aria-labelledby="navbarDropdownHI">
                    <li><a class="dropdown-item" href="#">Action</a></li>
                  <li class="nav-item dropdown"><a class="dropdown-item dropdown-toggle" href="#">Submenu</a>
                    <ul class="dropdown-menu">
                      <li><a class="dropdown-item" href="#">Submenu action</a></li>
                      <li><a class="dropdown-item" href="#">Another submenu action</a></li>
                    </ul>
                  </li>                
                  <li class="dropdown-divider"></li>
                  <li><a class="dropdown-item" href="#">View All</a></li>
                </ul>
              </li>
        <li class="nav-item">
          <a class="nav-link disabled" href="#">Disabled</a>
        </li>
      </ul>     
    </div>
  </nav>

Answer 1

You need to add custom styles along with the following html

.dropdown-submenu {
  position: relative;
}

.dropdown-submenu>.dropdown-menu {
  top: 0;
  left: 100%;
  margin-top: -6px;
  margin-left: -1px;
  -webkit-border-radius: 0 6px 6px 6px;
  -moz-border-radius: 0 6px 6px;
  border-radius: 0 6px 6px 6px;
}

.dropdown-submenu:hover>.dropdown-menu {
  display: block;
}

.dropdown-submenu>a:after {
  display: block;
  content: " ";
  float: right;
  width: 0;
  height: 0;
  border-color: transparent;
  border-style: solid;
  border-width: 5px 0 5px 5px;
  border-left-color: #ccc;
  margin-top: 5px;
  margin-right: -10px;
}

.dropdown-submenu:hover>a:after {
  border-left-color: #fff;
}

.dropdown-submenu.pull-left {
  float: none;
}

.dropdown-submenu.pull-left>.dropdown-menu {
  left: -100%;
  margin-left: 10px;
  -webkit-border-radius: 6px 0 6px 6px;
  -moz-border-radius: 6px 0 6px 6px;
  border-radius: 6px 0 6px 6px;
}

<div class="container">
  <div class="row">
    <div class="dropdown">
      <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                  Dropdown
        </button>
      <ul class="dropdown-menu multi-level" role="menu" aria-labelledby="dropdownMenu">
        <li class="dropdown-item"><a href="#">Some action</a></li>
        <li class="dropdown-item"><a href="#">Some other action</a></li>
        <li class="dropdown-divider"></li>
        <li class="dropdown-submenu">
          <a class="dropdown-item" tabindex="-1" href="#">Hover me for more options</a>
          <ul class="dropdown-menu">
            <li class="dropdown-item"><a tabindex="-1" href="#">Second level</a></li>
            <li class="dropdown-submenu">
              <a class="dropdown-item" href="#">Even More..</a>
              <ul class="dropdown-menu">
                <li class="dropdown-item"><a href="#">3rd level</a></li>
                <li class="dropdown-submenu"><a class="dropdown-item" href="#">another level</a>
                  <ul class="dropdown-menu">
                    <li class="dropdown-item"><a href="#">4th level</a></li>
                    <li class="dropdown-item"><a href="#">4th level</a></li>
                    <li class="dropdown-item"><a href="#">4th level</a></li>
                  </ul>
                </li>
                <li class="dropdown-item"><a href="#">3rd level</a></li>
              </ul>
            </li>
            <li class="dropdown-item"><a href="#">Second level</a></li>
            <li class="dropdown-item"><a href="#">Second level</a></li>
          </ul>
        </li>
      </ul>
    </div>
  </div>
</div>