uilang.js

const code = `clicking on ".container" add class "active" on it`;

   //  
   
 const compose = (...funcs) => value => funcs.reduceRight((a, b) => b(a), value);
 const flatten = (arr) => { return Array.isArray(arr) ? [].concat.apply([], arr) : [arr] };
  
const findBlocks = () => {
  let codeBlocks = [...document.querySelectorAll('code')];
 // return codeBlocks.map(codeBlock => codeBlock.textContent.trim())  
  return codeBlocks.map(codeBlock => code.trim()).join()
}

const textParser = (codeContents) => {
    let delimiter  = 'clicking on ';
    return codeContents.split(delimiter).map(content => 
     content.split(' ')
    ).slice(1);
};

const domEvents = (tokens) => {

  let callback = (target,classie,behavior) => (event) => {
     let classToggle = (el) => el.classList[behavior](classie);
     ['target','itself','self','it','this'].includes(target) ? 
                   classToggle(event.currentTarget) :
                   0// [...document.querySelectorAll(target)].forEach(classToggle)
  }
  
   for(let [el,behavior,,classie,,target] of (tokens)) {
       console.log(el,behavior,classie,target);

       document.querySelectorAll(el.replace(/"/g,'')).forEach(elem=>{
         console.log(elem)
         elem.tagName && elem.addEventListener('click',callback(target,classie,behavior))
     })
   }
}

let uilang = compose(
  domEvents,
  textParser,
  findBlocks
);

uilang('');