In this gist i will try to explain memoization in javascript

memoization_in_javascript.js

const notMemoized = (x) => {
  return x*2;
}

notMemoized(2); // 4
notMemoized(2); // 4
// every time we run the function the multiplication code get executed which can be optimized by memoization

const memoizedFn = () => {
  const cache = {};
  return (x) => {
      if( x in cache ) {
        return cache[x];
      }  else {
        return x*2;
      }
  }
}

const multiply = memoizedFn();
multiply(2); // 4
multiply(2); // 4 return from cache as the parameter is same so the return value is memoized