简单函数返回“未定义"值 [英] Simple function returning 'undefined' value

问题描述

这是我目前正在使用的功能:

This is the function I am currently working on:

function getSmallestDivisor(xVal) {    

    if (xVal % 2 === 0) {
        return 2;
    } else if (xVal % 3 === 0) {
        return 3;
    } else {
        var xSqrt = Math.sqrt(xVal);

        if (xSqrt % 1 === 0) {
            getSmallestDivisor(xSqrt);
        } else { 
            return xVal;
        }
    }

}

alert(getSmallestDivisor(121));

我已经设计了上面的函数来返回整数的最低除数.考虑情况 121 .它实际上应该在当前上下文中返回 11 .但它返回的是 undefined .

I had designed the above function to return the lowest divisor of an integer. Consider the case 121. It should actually return 11 in the current context. But it is returning undefined.

我检查了递归调用发生了多少次；他们实际上发生了两次.我在这两个不同的调用中记录了 xVal 的值，它们显示了 121 和 11 .我在这里真的很困惑为什么此函数当前返回 undefined .

I have checked how many times the recursive calls happened; they actually happened two times. I logged the values of xVal in those two different calls, and they display 121 and 11. I am really confused here about why this function is currently returning undefined.

我创建了一个jsfiddle演示.

推荐答案

if (xSqrt % 1 === 0) {
    return getSmallestDivisor(xSqrt); // missing return here
} else {
    return xVal;
}

演示:小提琴

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