Implement memoize(fn)

Question

Write a `memoize` function that caches the results of function calls. Subsequent calls with the same arguments should return the cached result without re-running the function.

Accepted Answer

function memoize(fn) {
  const cache = new Map()

return function (...args) {
    const key = JSON.stringify(args)
    if (cache.has(key)) return cache.get(key)

const result = fn.apply(this, args)
    cache.set(key, result)
    return result
  }
}

// Usage
function expensiveFib(n) {
  if (n <= 1) return n
  return expensiveFib(n - 1) + expensiveFib(n - 2)
}
const fib = memoize(expensiveFib)
fib(40) // computed
fib(40) // instant cache hit

Implement memoize(fn)

Answer