Memoization is an optimization technique that speeds up applications by storing the results of expensive function calls and returning the cached result when the same inputs occur again. Check it out -> https://jsbench.me/foktstl85t/1

memoized-fibonacci-JSbench.md

function fibonacci(n) {
  if (n <= 1) {
    return 1
  }

  return fibonacci(n - 1) + fibonacci(n - 2);
}

function memoizedFibonacci(n, memo) {
  memo = memo || {}

  if (memo[n]) {
    return memo[n]
  }

  if (n <= 1) {
    return 1
  }
  
  return memo[n] = memoizedFibonacci(n - 1, memo) + memoizedFibonacci(n - 2, memo)
}

function memoizedFibonacci2(n, memo) {
  memo = memo || {}

  if (memo[n]) {
    return memo[n]
  }

  if (n <= 1) {
    return 1
  }
  
  return memo[n] = memoizedFibonacci2(n - 2, memo) + memoizedFibonacci2(n - 1, memo)
}

function memoizer(fun) {
  let cache = {}

  return function(n) {
    if (cache[n] != undefined ) {
      return cache[n]
    } else {
      let result = fun(n)
      cache[n] = result

      return result
    }
  }
}

const fibonacciMemoFunction = memoizer(fibonacci)
const fibonacciMemoFunction2 = memoizer(memoizedFibonacci)