JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>

<head>
    <title>Page Title</title>
</head>

<body>
    <custom-toggle checked="true"></custom-toggle>
    <button onclick="test()">Change State</button>
    <script>
        function test() {
            var toggle = document.querySelector('custom-toggle');
            toggle.checked = !toggle.checked;
        }
    </script>
    <script type="module">
    const template = document.createElement('template');
template.innerHTML = `
<style>



/* The switch - the box around the slider */
.switch {
  position: relative;
  display: inline-block;
  width: 60px;
  height: 34px;
}


/* Hide default HTML checkbox */
.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

/* The slider */
.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 26px;
  width: 26px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  -webkit-transition: .4s;
  transition: .4s;
}

input:checked + .slider {
  background-color: #2196F3;
}

input:focus + .slider {
  box-shadow: 0 0 1px #2196F3;
}

input:checked + .slider:before {
  -webkit-transform: translateX(26px);
  -ms-transform: translateX(26px);
  transform: translateX(26px);
}

/* Rounded sliders */
.slider.round {
  border-radius: 34px;
}

.slider.round:before {
  border-radius: 50%;
}
</style>
<label class="switch">
  <input type="checkbox">
  <span class="slider round"></span>
</label>
`

export class customToggle extends HTMLElement {
  #shadowRoot;
  #input;

  static get observedAttributes() {
    return ['checked', 'enabled'];
  }

  constructor() {
    super();

    this.#shadowRoot = this.attachShadow({
      mode: 'closed'
    });
    this.#shadowRoot.appendChild(template.content.cloneNode(true));
    this.#input = this.#shadowRoot.querySelector('input');
  }

  get checked() {
    return this.getAttribute('checked')...