JS Memoization example.

memoization.js

//To run this example : node memoization.js

'use strict'

var start, result, end;

var fibo = function fibonacci(n) {
    if (n < 2) {
        return n;
    } else {
        return fibonacci(n - 1) + fibonacci(n - 2)
    }
};

var memoFibo = (function fibonacci() {
    var memo = [0, 1];
    return function fib(n) {
        var result = memo[n];
        if (typeof result !== 'number') {
            result = fib(n - 1) + fib(n - 2);
            memo[n] = result;
        }
        return result;
    };
})();

start = process.hrtime();
result = fibo(40);
end = process.hrtime(start);
console.info("fibo result : %s - Execution time : %ds %dms", result, end[0], end[1]/1000000);

start = process.hrtime();
result = memoFibo(40);
end = process.hrtime(start);
console.info("memoFibo result : %s - Execution time : %ds %dms", result, end[0], end[1]/1000000);