SOURCE

function factorial(num){
    if(num<=1){
        return 1
    }else{
        return num *factorial(num - 1)
    }
}
let num1 = factorial(5)
console.log(num1)



function factorial(num){
    if(num<=1){
        return 1
    }else{
        return num *arguments.callee(num - 1)
    }
}
let num2 = factorial(5)
console.log(num2)



// caller 这个属性引用的是调用当前函数的函数
function outer(){
    inner()
}

function inner(){
    console.log(inner.caller)
}

outer()