JavaScript递归函数

function fibonacciSequence(n) {
            if(n == 1 || n == 2){
                return 1;
            }else if(n == 3){
                return fibonacciSequence(2) + fibonacciSequence(1);
            }else if(n == 4){
                return fibonacciSequence(3)+fibonacciSequence(2);
            }else if(n == 5){
                return fibonacciSequence(4) + fibonacciSequence(3);
            }else if(n == 6){
                return fibonacciSequence(5) + fibonacciSequence(4);
            }
           //·········
            else if(n == n){
                return fibonacciSequence(n-1) + fibonacciSequence(n-2)
            };
        };
        console.log(fibonacciSequence(10));