JSFiddle - React, Tailwind, and code Playground

HTML

<button type="button" class="btn">
  <span class="btn-stage"></span>
  <span class="btn-text">button</span>
</button>

CSS

body{
  background: #212121
}
.btn{
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate3d(-50%,-50%,0);
  border: 2px solid #616161;
  width: 184px;
  height: 40px;
  border-radius: 50px;
  background: #212121;
  color: #EEEEEE;
  overflow: hidden;
  line-height: 36px;
  outline: none;
  cursor: pointer;
  transition: all 1s ease;
}
.btn.charged{
  border-color: #8BC34A;
  box-shadow: 0 0 5px #000000, 0 0 50px 5px #8BC34A;
}
.btn-stage{
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  text-align: left;
}
.btn-stage:after{
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  box-shadow: inset 0 0 1px 1px #000;
  opacity: .4;
}
.btn-stage i{
  display: inline-block;
  width: 3.3333%;
  height: 100%;
    background: linear-gradient(to bottom, #a0da5c, #71a237 50%, #567d28 50%, #6f9e39 100%);
    box-sizing: border-box;
    box-shadow: inset 1px 0 0 rgba(255, 255, 255, 0.1), inset -1px 0 0 rgba(0, 0, 0, 0.2);
}
.btn-text{
  z-index: 3;
  text-shadow: 1px 1px #333;
  display: block;
  position: absolute;
  top: 8px;
  left: 0;
  right: 0;
  width: 60px;
  margin: 0 auto;
  background: rgba(33, 33, 33, 0.5);
  line-height: 20px;
  border-radius: 30px;
}

JavaScript

var $stage = document.querySelector('.btn-stage'),
		i = 0;

document.querySelector('.btn').addEventListener('click', function(e){
	e.preventDefault();
  
	if(i < 30)
	{
		var bar = document.createElement('i');
  
		$stage.appendChild(bar);
  
  	i++;
	}
  
  if(i == 30)
  {
  	document.querySelector('.btn').classList.add('charged');
  }
})