"Вспышка" background-color при клике на кнопке

let button = document.querySelector('button'); 
 
button.addEventListener('click', function(e){ 
  button.classList.add('b'); 
  setTimeout( () => { 
       button.classList.remove('b'); 
  }, 500) 
});

.b{ 
    background-color: red; 
    transition: 0.5s; 
  }

<button>text</button>

(function($) { 
  $('.div1').on("click", function() { 
    var elem = $('.div2'); 
    elem.addClass("testa"); 
    setTimeout(function() { 
      elem.removeClass('testa'); 
    }, 300); 
  }); 
})(jQuery);

.testa { 
  background-color: red; 
  box-shadow: 0px 0px 40px 20px red; 
  transition: background-color 100ms linear, box-shadow 0.5s ease-in-out; 
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
<div id="div1" class="div1">div1</div> 
<div id="div2" class="div2">div2</div>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
<div id="div1" class="div1">Кнопка</div> 
 
<script>(function($) { 
        $('div').on("click", function(){ 
            var elem = $(this); 
            elem.css('background', 'red'); 
            elem.css('transition-property', 'background-color'); 
            elem.css('transition-duration', '1s'); 
            setTimeout(function(){ 
                elem.css('background', ''); 
            }, 500); 
        }); 
    })(jQuery); 
</script>