JavaScript递归函数定义与用法实例分析

function factorial(num) {
  if (num <= 1) {
    return 1;
  } else {
    return num * factorial(num - 1);
  }
}

var anotherFactorial = factorial;
factorial = null;
console.log(anotherFactorial(4));//出错

function factorial(num) {
  if (num <= 1) {
    return 1;
  } else {
    return num * arguments.callee(num - 1);
  }
}
var anotherFactorial = factorial;
factorial = null;
console.log(anotherFactorial(4));

var factorial = (
    function f(num) {
      if (num <= 1) {
        return 1;
      } else {
        return num * f(num - 1);
      }
    }
);
var anotherFactorial = factorial;
factorial = null;
console.log(anotherFactorial(4));