Solution 1 :

Your code do work, but you need to make the .toggle visible so that you can click on it. Not pretty, but shows how it could work:

$(function() {
      $('.toggle').on('click', function() {
        $('.wrapper').toggleClass('open');
      });
    });
.wrapper {
    transform: translateX(0px);
    transition: transform .4s ease;
}

.wrapper.open {
    transform: translateX(280px);
}

 #main-nav {
    transform: translateX(-280px);
}

.toggle {
  background-color: grey;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="wrapper">
    <nav id="main-nav">
        <div class="menu-btn toggle">|Menu|</div>
        <ul>
          <li>Item 1</li>
          <li>Item 2</li>
          <li>Item 3</li>
        </ul>
    </nav>
</div>

Solution 2 :

Your code seems to work almost, since JQuery was missing and a overkill in this situation I’ve rewritten it a little. Also needed to add some content for the menu and button to make it visible. The code you showed wasn’t enough to reproduce the problem. 😉

I would also advice to use an actual button tag for interactions like this, for accessibility reasons (native support for keyboard interaction).

If you’re interested: https://developer.mozilla.org/en-US/docs/Learn/Accessibility/HTML

const body = document.body; // Get the document body

// Get your menu with a special JS class, prevents accidents when other
// developers will use your code later on (seperate JS functions from styling classes).
const menuToggle = document.querySelector('.js-site-menu');
// Set a classname to use lateron (DRY).
const menuToggleClass = "is-open";

// Add event to listen to.
menuToggle.addEventListener("click", (event) => {
  // Get current clicked object/target.
  let currentTarget = event.currentTarget;
  // Check if opened class is present on body
  let menuOpened = body.classList.contains(`${menuToggleClass}`);

  // Check if menu is already open.
  if (!menuOpened) {
    // Adds class to body when not opened
    body.classList.add(`${menuToggleClass}`);
  } else {
    // Removes class from body when menu is already opened
    body.classList.remove(`${menuToggleClass}`);
  }
});
`/* Used percentages(%) instead of a fixed px size for easier responsive behaviour later on the road. */`
.main-nav {
  transform: translateX(-101%);
  transition: transform .4s ease;
}

.is-open .main-nav {
  transform: translateX(0%);
}

.main-nav_button {
  position: absolute;
  top: 0;
  right: 0;
}
<div class="wrapper">
  <button type="button" class="main-nav_button js-site-menu">Menu</button>
  <nav class="main-nav">
    <ul>
      <li>Menu item 1</li>
      <li>Menu item 2</li>
      <li>Menu item 3</li>
      <li>Menu item 4</li>
    </ul>
  </nav>
</div>

Problem :

I want to push my menu with the content also being pushed to the right, but for some reason the JS code doesn’t get the job done. <div class="menu-btn toggle"></div> doesn’t trigger the menu. Can somebody tell me why and how to fix it?

JS

$(function() {
      $('.toggle').on('click', function() {
        $('.wrapper').toggleClass('open');
      });
    });

CSS

.wrapper {
    transform: translateX(0px);
    transition: transform .4s ease;
}

.wrapper.open {
    transform: translateX(280px);
}

 #main-nav {
    transform: translateX(-280px);
}

HTML

<div class="wrapper">
    <nav id="main-nav">
        <div class="menu-btn toggle"></div>
        <ul></ul>
    </nav>
</div>

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