无法读取null属性进行破坏

Question

销毁很酷，但是在销毁嵌套对象时我开始遇到严重的问题。我有以下代码：

const {
      credit: { amont },
    } = userProfile

这很危险，因为如果信用为空怎么办？整个应用中断了。我该如何预防？我知道一种方法是使用Typescript，但我宁愿不这样做。我开始怀疑对嵌套的破坏与使用点没有什么区别。

Answer 1

It isn't possible to solve this with deep destructuring. As another answer suggests, it's possible to use default values but they are applied only to undefined values:

const { credit: { amont } = {} } = userProfile || {};

While null values still result in error, it's necessary to do short-circuit evaluation for all objects that can potentially be nully:

const { credit } = userProfile || {};
const { amont } = credit || {};

This can be addressed with safe navigation utility function that reads the path and checks for nully values.

A renowned example is Lodash get:

const amont = _.get(userProfile, 'credit.amont');

我知道一种方法是使用打字稿，但在这里我不

仅在保证类型安全的情况下，才可以使用TypeScript解决此问题。如果userProfile来自JSON响应，则必须应用运行时类型检查来断言对象不是null。