Nodejs Utililty Methods HTML Element Class Add

Element.prototype.addClass = function(className) {
  const currentClasses = this.className
  this.className = `${currentClasses} ${className}`.trim()
  return this

Element.prototype.addClass=function(className){
  var classNames=this.className.split(' ');
  for(var i=0;i<classNames.length;i++){
    if(classNames[i]===className){
      return true;
  this.className+=' '+className;
  return true;
...

Element.prototype.addClass = function(className){
  var existing = this.className.length, spacer = "";
  if(existing > 0) spacer = " "; 
  if (!this.hasClass(className)) this.className = (this.className + spacer + className);
  return this;

Element.prototype.addClass = function(cls) {
  if (!this.hasClass(cls)) { this.className += " " + cls; }
};

Element.prototype.pushClass = function(className){
  this.className += ' ' +className

HTMLElement.prototype.styles = function (css) {
    for (var property in this.style) {
        if (css[property]) this.style[property] = css[property];

Element.prototype.addStyleClass = function(className) {
    if (className && !this.hasStyleClass(className))
        this.className += (this.className.length ? " " + className : className);
};