javascript - 如何读取对象内值的长度？

Question

我有下面的代码:

const minLocationLength = 1;
        if (location.description.length < minLocationLength) {
          reject(`Location must be at least ${minLocationLength} characters.`);
        }

我收到错误无法读取未定义的属性“长度”。我这样做对吗？

Answer 1

description的值没有定义，你应该先这样检查:

 if (location.description && location.description.length < minLocationLength) {
          reject(`Location must be at least ${minLocationLength} characters.`);
        }