Some fun with `setImmediate`

fibonacci-eventlooped.js

function fibonacciProcessed(x) {
    return new Promise(resolve => {
        const calculation = function (resolveFn, n = 0, a = 0, b = 1) {
            if (n > 1) {
                setImmediate(() => {
                    calculation(resolveFn, n - 1, b, a + b);
                });
            }

            // else
            resolveFn(b);
        };

        calculation(resolve, x);
    });
}

fibonacciProcessed(1476).then(number => {
    console.log(number);
});

// counter concepts

// anti-example, will be slower and slower, eventually reaching vaporwave sampling level
// function fibonacci(x) {
//     return x <= 1 ? x : fibonacci(x - 1) + fibonacci(x - 2);
// }
//
// console.log(fibonacci(process.argv[2]));

// as above, just with normal returns -- works just the same
// function fib(a, b, n) {
//     if (n) {
//         return fib(b, a + b, n - 1);
//     }
//
//     return a;
// }
// console.log(fib(0, 1, 1476));