JS how to cache a variable

Question

What I want to do is to be able to create a variable, give it a value, close and reopen the window, and be able to retrieve the value I set in the last session. What is the

Answer 1

I have written a generic caching func() which will cache any variable easily and very readable format. Caching function:

function calculateSomethingMaybe(args){
  return args;
}

function caching(fn){
  const cache = {};
  return function(){
    const string = arguments[0];
    if(!cache[string]){
      const result = fn.apply(this, arguments);
      cache[string] = result;
      return result;
    }
    return cache[string];
  }
}

const letsCache = caching(calculateSomethingMaybe);

console.log(letsCache('a book'), letsCache('a pen'), letsCache('a book'));