Collapsed container

by Anton Spirin

HTML

<script src="https://code.jquery.com/jquery-3.2.1.js"></script>
<div class="collapsed-container js-collapsed-container">
  <div class="collapsed-container__text-wrapper js-collapsed-container__text-wrapper">
    <div class="collapsed-container__text js-collapsed-container__text">
   Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
   </div>
  </div>
  <div class="collapsed-container__toggler js-collapsed-container__toggler" data-text-toggle="Скрыть">
    Читать полностью
  </div>
</div>

CSS

* {
  box-sizing: border-box;
}
.collapsed-container {
  width: 300px;
  border: 1px solid black;
}

.collapsed-container__text-wrapper {
  margin: 10px;
  overflow: hidden;
  height: 90px;
}

.collapsed-container__toggler {
  border-top: 1px solid black;
  padding: 10px;
  text-align: center;
  cursor: pointer;
}

JavaScript

$('.js-collapsed-container').on('click', '.js-collapsed-container__toggler', function(e) {
  e.preventDefault();
  
  const toggler = $(e.currentTarget);
  const container = $(e.delegateTarget);
  const textWrapper = container.children('.js-collapsed-container__text-wrapper');
  const togglerText = toggler.html();
  const textHeight = textWrapper.children('.js-collapsed-container__text').height();

  container.toggleClass('js-collapsed-container--opened');
  toggler.html(toggler.data('text-toggle'));
  toggler.data('text-toggle', togglerText);
  
  const newHeightValue = container.hasClass('js-collapsed-container--opened') ?  textHeight : 90;
  
  textWrapper.animate({ height: newHeightValue + 'px' }, 'medium');
});