dom.js

const $ = function (selector) {
  const nodeList = document.querySelectorAll(selector);

  const text = function(content){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].innerText = content;
    }
  }

  const html = function(content){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].innerHTML = content;
    }
  }

  const addClass = function(className){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].classList.add(className);
    }
  }

  const removeClass = function(className){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].classList.remove(className);
    }
  }

  const toggleClass = function(className){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].classList.toggle(className);
    }
  }

  const empty = function(){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].innerHTML = '';
    }
  }

  const append = function(content){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].innerHTML += content;
    }
  }

  const prepend = function(content){
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].innerHTML = content + nodeList[i].innerHTML;
    }
  }

  const val = function (content) {
      if(content === undefined){
        return nodeList[0].value;
      } else {
        nodeList[0].value = content;
      }
  }

  const on = function (action, cb) {
    for (let i = 0; i < nodeList.length; i++) {
      nodeList[i].addEventListener(action, cb);
    }
  }

  return {
    text: text,
    html: html,
    addClass: addClass,
    removeClass: removeClass,
    toggleClass: toggleClass,
    empty: empty,
    append: append,
    prepend: prepend,
    on: on,
    val: val
  };
}