>fib(n) => n < 2 ? n : (fib(n - 1) + fib(n - 2)); + the laziest way to do memoization: var cache = new Map(); fib (n) => cache.putIfAbsent(n, () => n < 2 ? n

>fib(n) => n < 2 ? n : (fib(n - 1) + fib(n - 2)); + the laziest way to do memoization: var cache = new Map(); fib (n) => cache.putIfAbsent(n, () => n < 2 ? n : fib(n - 1) + fib(n - 2));