SOURCE

let toggleB = document.getElementById('button');
let aside = document.getElementById('div1');
button.addEventListener('click', toggleHandle, false)

// let reg = new RegExp('(\\s*)toggle(\\s*)');
// function toggleHandle() {
//   if (aside.className.includes('toggle')){
    
//     aside.className = aside.className.replace(reg, " ");
    
//   } else {
//     aside.className = aside.className + ' toggle';
//   }
//   console.log('aside.className', aside.className)
// }
function toggleHandle() {
  aside.classList.toggle('toggle')
}

<div id="div1" class="toggle test">test</div>
<button id="button" type="button">test</button>

#div1 {
  background-color: pink;
  height: 100px;
  width: 200px;
  position: fixed;
  right: 0;
  transition: transform .3s cubic-bezier(.16,.22,.22,1.7);
}
.toggle {
    transform: translateX(110%);
}