fullText.js

fullText.js

function fullText() {
  var elements = [].slice.call(document.querySelectorAll('[data-full-text]'));
    elements.forEach(function(element) {
    var REGEX_NUMBER = /\d+/;
    var REGEX_NO_NUMBER = /[^\d]+/;
    element.style.display = "inline";
    element.style.fontSize = '';
    var width = element.getBoundingClientRect().width;
    var containerWidth = element.parentNode.getBoundingClientRect().width;
    var fontSize = getComputedStyle(element).fontSize;
    var fontSizeValue = fontSize.match(REGEX_NUMBER)[0];
    var fontSizeUnit = fontSize.match(REGEX_NO_NUMBER)[0];
  
    var newFontSize = (fontSizeValue/width)*containerWidth;
  
    element.style.display = '';
    element.style.fontSize = newFontSize + fontSizeUnit;
  });
}

window.addEventListener('DOMContentLoaded', fullText);
window.addEventListener('resize', fullText);