<button id="clap" class="clap">
  <span>
    <!--  SVG Created by Luis Durazo from the Noun Project  -->
    <svg id="clap--icon" xmlns="http://www.w3.org/2000/svg" viewBox="-549 338 100.1 125">
  <path d="M-471.2 366.8c1.2 1.1 1.9 2.6 2.3 4.1.4-.3.8-.5 1.2-.7 1-1.9.7-4.3-1-5.9-2-1.9-5.2-1.9-7.2.1l-.2.2c1.8.1 3.6.9 4.9 2.2zm-28.8 14c.4.9.7 1.9.8 3.1l16.5-16.9c.6-.6 1.4-1.1 2.1-1.5 1-1.9.7-4.4-.9-6-2-1.9-5.2-1.9-7.2.1l-15.5 15.9c2.3 2.2 3.1 3 4.2 5.3zm-38.9 39.7c-.1-8.9 3.2-17.2 9.4-23.6l18.6-19c.7-2 .5-4.1-.1-5.3-.8-1.8-1.3-2.3-3.6-4.5l-20.9 21.4c-10.6 10.8-11.2 27.6-2.3 39.3-.6-2.6-1-5.4-1.1-8.3z"/>
  <path d="M-527.2 399.1l20.9-21.4c2.2 2.2 2.7 2.6 3.5 4.5.8 1.8 1 5.4-1.6 8l-11.8 12.2c-.5.5-.4 1.2 0 1.7.5.5 1.2.5 1.7 0l34-35c1.9-2 5.2-2.1 7.2-.1 2 1.9 2 5.2.1 7.2l-24.7 25.3c-.5.5-.4 1.2 0 1.7.5.5 1.2.5 1.7 0l28.5-29.3c2-2 5.2-2 7.1-.1 2 1.9 2 5.1.1 7.1l-28.5 29.3c-.5.5-.4 1.2 0 1.7.5.5 1.2.4 1.7 0l24.7-25.3c1.9-2 5.1-2.1 7.1-.1 2 1.9 2 5.2.1 7.2l-24.7 25.3c-.5.5-.4 1.2 0 1.7.5.5 1.2.5 1.7 0l14.6-15c2-2 5.2-2 7.2-.1 2 2 2.1 5.2.1 7.2l-27.6 28.4c-11.6 11.9-30.6 12.2-42.5.6-12-11.7-12.2-30.8-.6-42.7m18.1-48.4l-.7 4.9-2.2-4.4m7.6.9l-3.7 3.4 1.2-4.8m5.5 4.7l-4.8 1.6 3.1-3.9"/>
</svg>
  </span>
  <span id="clap--count" class="clap--count"></span>
  <span id="clap--count-total" class="clap--count-total"></span>
</button>
/*========================
    SASS definitions
  =======================*/
$btn-dimension: 80px;
$primary-color: rgba(189,195,199 ,1);
$secondary-color: rgba(39,174,96 ,1);
@mixin debug {
  outline: 1px solid red;
}

/*========================
    FLEXBOX ALIGNMENT 
  =======================*/
body {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
}

/*========================
    BASIC styles
  =======================*/
* {
  box-sizing: border-box
}

/*========================
    BUTTON styles
  =======================*/
.clap {
  position: relative;
  outline: 1px solid transparent;
  border-radius: 50%;
  border: 1px solid $primary-color;
  width: $btn-dimension;
  height: $btn-dimension; 
  background: none;
  &:after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    display: block;
    border-radius: 50%;
    //border: 1px solid $primary-color;
    width: $btn-dimension - 1px;
    height: $btn-dimension - 1px;
  }
  &:hover {
   cursor: pointer;
   border: 1px solid $secondary-color;
   transition: border-color 0.3s ease-in;
    &:after {
      animation: shockwave 1s ease-in infinite;
    } 
  }
  svg {
    width: 40px;
    fill: none;
    stroke: $secondary-color;
    stroke-width: 2px;
    &.checked {
      fill: $secondary-color;
      stroke: #fff;
      stroke-width: 1px;
    }
  }
  .clap--count {
    position: absolute;
    top: -$btn-dimension/1.6;
    left: $btn-dimension/4;
    font-size: 0.8rem;
    color: white;
    background: $secondary-color;
    border-radius: 50%;
    height: $btn-dimension/2;
    width: $btn-dimension/2;
    line-height: $btn-dimension/2;
  }
  .clap--count-total {
    position: absolute;
    font-size: 0.8rem;
    width: $btn-dimension;
    text-align: center;
    left: 0;
    top: -$btn-dimension/3.5;
    color: $primary-color; 
  }
}



/*====================
        Message
======================*/
#message {
  position: absolute;
  bottom: 20px;
  color: $secondary-color;
  line-height: 1.52rem;
  padding: 1rem;
  font-size: 0.9rem;
  a {
    color: $primary-color
  }
}



@keyframes shockwave {
  0% {
    transform: scale(1);
    box-shadow: 0 0 2px $secondary-color;
    opacity: 1;
  }

  100% {
    transform: scale(1);
    opacity: 0;
    box-shadow: 0 0 50px darken($secondary-color, 20%), inset 0 0 10px $secondary-color;
  }
}
const clap = document.getElementById('clap')
const clapIcon = document.getElementById('clap--icon')
const clapCount = document.getElementById('clap--count')
const clapTotalCount = document.getElementById('clap--count-total')
const initialNumberOfClaps = generateRandomNumber(500, 10000);
const btnDimension = 80
const tlDuration = 300
let numberOfClaps = 0
let clapHold;

const triangleBurst = new mojs.Burst({
  parent: clap,
  radius: {50:95},
  count: 5,
  angle: 30,
  children: {
    shape: 'polygon',
    radius: {6: 0},
    scale: 1,
    stroke: 'rgba(211,84,0 ,0.5)',
    strokeWidth: 2,
    angle: 210,
    delay: 30,
    speed: 0.2,
    easing: mojs.easing.bezier(0.1, 1, 0.3 ,1),
    duration: tlDuration
  } 
})
const circleBurst = new mojs.Burst({
  parent: clap,
  radius: {50:75},
  angle: 25,
  duration: tlDuration,
  children: {
    shape: 'circle',
    fill: 'rgba(149,165,166 ,0.5)',
    delay: 30,
    speed: 0.2,
    radius: {3: 0},
    easing: mojs.easing.bezier(0.1, 1, 0.3, 1),
  }
})
const countAnimation = new mojs.Html({
  el: '#clap--count',
  isShowStart: false,
  isShowEnd: true,
  y: {0: -30},
  opacity: {0:1},
  duration: tlDuration
}).then({
  opacity: {1:0},
  y: -80,
  delay: tlDuration/2
})
const countTotalAnimation = new mojs.Html({
  el: '#clap--count-total',
  isShowStart: false,
  isShowEnd: true,
  opacity: {0:1},
  delay: 3*(tlDuration)/2,
  duration: tlDuration,
  y: {0: -3}
})
const scaleButton = new mojs.Html({
  el: '#clap',
  duration: tlDuration,
  scale: {1.3: 1},
  easing: mojs.easing.out
})
clap.style.transform = "scale(1, 1)" /*Bug1 fix*/

const animationTimeline = new mojs.Timeline()
animationTimeline.add([
  triangleBurst,
  circleBurst,
  countAnimation,
  countTotalAnimation,
  scaleButton
])


clap.addEventListener('click', function() {
   repeatClapping();
})

clap.addEventListener('mousedown', function() {
   clapHold = setInterval(function() {
   repeatClapping();
   }, 400)
})

clap.addEventListener('mouseup', function() {
 clearInterval(clapHold);
})


function repeatClapping() {
 updateNumberOfClaps()
 animationTimeline.replay()
 clapIcon.classList.add('checked')
}

function updateNumberOfClaps() {
  numberOfClaps < 50 ? numberOfClaps++ : null
  clapCount.innerHTML = "+" + numberOfClaps
  clapTotalCount.innerHTML = initialNumberOfClaps + numberOfClaps
}

function generateRandomNumber(min, max) {
  return Math.floor(Math.random()*(max-min+1)+min);
}

/*====== TODO ==========
1. Bug fix. The button shouldn't 
scale up before being clicked (fixed)
2. Shadow should NOT fire hover 
animation in succession. 
Some sort of delay is delay.
3. Hover animation should be 
absent upon click
4. Handle onpress event on the button
5. Dynamically change burst angle 
everytime button is clicked
=========================*/
View Compiled

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/mo-js/0.288.1/mo.min.js