removeClass.js

function replaceClassName(origClass, classToRemove) {
  return origClass.replace(new RegExp("(^|\\s)" + classToRemove + "(?:\\s|$)", 'g'), '$1').replace(/\s+/g, ' ').replace(/^\s*|\s*$/g, '');
}

export default function removeClass(element, className) {
  if (element.classList) {
    element.classList.remove(className);
  } else if (typeof element.className === 'string') {
    ;
    element.className = replaceClassName(element.className, className);
  } else {
    element.setAttribute('class', replaceClassName(element.className && element.className.baseVal || '', className));
  }
}