Vanilla JavaScript: Resize font-awesome to fit container

Question

I have been creating an audio player using vanilla JavaScript to manipulate the HTML <audio> element.

The player is of dynamic size, with all elements scaled to fit the parent DIV.

I have applied all methods I can find for scaling font to fit the parent container and combined solutions in a way that seems functional, however I cannot make font-awesome icons scale in the same way.

The icons are contained in the following way:

HTML:

<div>
  <button>
    <a>
      <i class="fa fa-play">
      </i>
    </a>
  </button>
</div>

My solution works by implementing window.addEventListener('resize', resizeFont);, with the resizeFont function defined as follows:

JavaScript:

function resizeFont() {
  var elements  = document.getElementsByClassName('resize');
  console.log(elements);
  if (elements.length < 0) {
    return;
  }
  _len = elements.length;
  for (_i = 0; _i < _len; _i++) {
    var el = elements[_i];
    el.style.fontSize = "100%";
    for (var size = 100; el.scrollHeight > el.clientHeight; size -= 10) {
      el.style.fontSize = size + '%';
    }
  }
}

I set font-size of the div,button or a element in CSS in order to provide some input for font-awesome's default font-size: inherit style.

The resizeFont(); function is called once on page load, ensuring that the fonts displayed are scaled to fit the audio player's initial size.

I have attempted to apply the .resize class to various elements with the following results:

div: font won't display, or font displays at default size and then disappears on window resize.

a: same result as div.

i: resizeFont() on window load does scale the icon to the correct size to fit the container, but the font still disappears when the window resize event is fired.

So, I guess that the .resize class is supposed to be applied to the i element, but that I somehow need to define its size, or its container's size, differently.

Answer 1

Add the class .jcfResize to any elements containing font which should be resized.

Add the following javascript code to the page/site:

function jcfResizeText() {
    var elements  = document.getElementsByClassName('jcfResize');
    if (elements.length < 0) {
        return;
    }
    _len = elements.length;
    for (_i = 0; _i < _len; _i++) {
        var el = elements[_i];
        el.style.fontSize = "100%";
        for (var size = 100; el.scrollHeight > el.clientHeight; size -= 10) {
            el.style.fontSize = size + '%';
        }
    }
}

jcfResizeText();
window.addEventListener('resize', jcfResizeText);