I've trying to create dropdown menu on click and close menu when clicked outside.
My currently problem is when i clicked on menu it only toggle or drop down only 1 menu, it doesn't toggle or dropdown on the other menu,
I've searching for the solution i found this one https://stackoverflow.com/a/3028037/14862921
function hideOnClickOutside(element) {
const outsideClickListener = event => {
    if (!element.contains(event.target) && isVisible(element)) { // or use: event.target.closest(selector) === null
      element.style.display = 'none'
      removeClickListener()
    }
}
const removeClickListener = () => {
    document.removeEventListener('click', outsideClickListener)
}
document.addEventListener('click', outsideClickListener)
}
const isVisible = elem => !!elem && !!( elem.offsetWidth || elem.offsetHeight || elem.getClientRects().length )
at the Edit – 2018-03-11 this is pure Javascrilpt, I want to apply this code to my project, honestly i'm new to Javascript i have no idea how to raplace the code to my project.
Any help or advices i will appreciate it. Thank you very much.
This is my project. https://jsfiddle.net/Yurael/7aju8x1k/14/
function dropDownMenu() {
    var btnNav = document.querySelector('.nav-menu');
    var dropSub = document.querySelector('.nav-dropdown');
    btnNav.addEventListener('click', function () {
        dropSub.classList.toggle('show');
    })
}
dropDownMenu();/*Block*/
.nav li {
    display: inline-block;
    list-style: none;
    color: black;
    width: 100px;
    height: auto;
    border: 1px solid red;
    font-size: 20px;
    text-align: center;
}
/*Element*/
.nav-dropdown {
    display: none;
    position: absolute;
}
.nav-dropdown li {
    position: relative;
    display: flex;
    left: -40%;
}
.show {
    display: block;
}    <ul class="nav">
        <li>Home</li>
        <li class="nav-menu">Menu1
            <ul class="nav-dropdown">
                <li>Example1</li>
                <li>Example2</li>
                <li>Example3</li>
            </ul>
        </li>
        <li class="nav-menu">Menu2
            <ul class="nav-dropdown">
                <li>Example1</li>
                <li>Example2</li>
                <li>Example3</li>
            </ul>
        </li>
    </ul> 
    