fib

by lbstr

JavaScript

var fib = function(n) {
    if (n < 1) { return 0; }
    if (n === 1) { return 1; }
    
    return fib(n-1) + fib(n-2);
};

// 1, 1, 2, 3, 5, 8, 13, 21...
alert(fib(1)); // should be 1
alert(fib(2)); // should be 1
alert(fib(4)); // should be 3
alert(fib(8)); // should be 21