lets understand how closure help in encapsulation

closure_encapsulation.js

function encapEg() {
  let protectedData = 0; // this is the protected data that we only want to allow read access not direct change it
  const accessTheData = () => protectedData; // this function will exported
  const updateData = ()=> protectedData++; // we want to update the protected data internall
  setInterval(updateData,1000); //this is the logic to update the data
  return {
    accessTheData // we return the function that only allow to access the protected data
  }
}

const obj = encapEg();
console.log(obj.accessTheData());

// In the above example we have varable protectData that has to protected means we dont want to give direct access to manipulate it, 
// we want to provide read ability, so we have created a function accessData which return the value of protected variable, this is all
// possible because of closure as on execution the function encapEg, it will be removed from the stack but the protectedData will not 
// be remove because it is refrenced by the accessTheData function and value will be save in the closure.