你能帮我我想打印阶乘 4 的值但是下面的函数总是给 NAN 为什么？

Question

My question is about recursive function why it is showing always NAN instead of showing the value of factorial 4.

function factorial(i){
              if (i == 1) { return;}  
              return i * factorial(--i);};        
      console.log(factorial(4));

Answer 1

function factorial(i){
              if (i == 1) { return 1;}  
              return i * factorial(--i);};        
      console.log(factorial(4));

Answer 2

if (i == 1) { return;} you should return number hear like return 1;

function factorial(i){
              if (i == 1) { return 1;}  
              return i * factorial(--i);};        
      console.log(factorial(4));