Convert Prototype JS to vanilla JS.

Question

I have the following piece of JS / prototypeJS, that I would like to write in full vanilla JS. I wish to click on an element (one out of a number of elements with the same class - faq-container) and add a specific class (in this case faq-display) and add this class only to the parent container (faq-block).

I understand that the pure JS function is something to do with .parent.addClass but can not find a relevant example to my situation.

The prototypeJs lines are:

faqContainers[i].addEventListener('click', function(e) { and

var faqToggle = e.target.up('.faq-block');

The script file is:

var faqContainers = document.getElementsByClassName('faq-container');

  for (var i = 0; i < faqContainers.length; i++) {
      faqContainers[i].addEventListener('click', function(e) {

        var faqToggle = e.target.up('.faq-block');

          if (faqToggle.classList.contains('faq-display')) {
              faqToggle.classList.remove('faq-display');
          } else {
              faqToggle.classList.add('faq-display');
          }

      });
}

Many thanks indeed!

Answer 1

Here's an example substituting closest() for PrototypeJS up():

  var faqContainers = document.getElementsByClassName('faq-container');

  for (var i = 0; i < faqContainers.length; i++) {
    faqContainers[i].addEventListener('click', function(e) {

      var faqToggle = e.target.closest('.faq-block');

      if (faqToggle.classList.contains('faq-display')) {
        faqToggle.classList.remove('faq-display');
      } else {
        faqToggle.classList.add('faq-display');
      }

    });
  }

  .faq {
    display: none;
  }
  .faq-block.faq-display .faq {
    display: block;
  }

  <div class="faq-container">
    <div class="faq-block">
      <h3>Headline</h3>
      <div class="faq">
        Lorem ipsum dolor sit amet, consectetur adipisicing 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="faq-block">
      <h3>Headline</h3>
      <div class="faq">
        Lorem ipsum dolor sit amet, consectetur adipisicing 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="faq-block">
      <h3>Headline</h3>
      <div class="faq">
        Lorem ipsum dolor sit amet, consectetur adipisicing 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="faq-block">
      <h3>Headline</h3>
      <div class="faq">
        Lorem ipsum dolor sit amet, consectetur adipisicing 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="faq-block">
      <h3>Headline</h3>
      <div class="faq">
        Lorem ipsum dolor sit amet, consectetur adipisicing 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>