如何避免在JavaScript中解构未定义的值?

Question

我得到响应registryReportSettings从服务器:

this.getRegistrySettings(registry.Id).subscribe((registryReportSettings: { extended: ReportPropertiesRequest }) => {
const { objectProperties, reportProperties, textProperties } = registryReportSettings?.extended;
}

如果是null，我得到一个错误:

TypeError: Cannot destructure property 'objectProperties' of '(intermediate value)(intermediate value)(intermediate value)' as it is undefined.

如何使用TS修复它?

Answer 1

错误意味着您试图解构一个可能的undefined(因为您使用可选链接)

你可以做

const { objectProperties, reportProperties, textProperties } = registryReportSettings?.extended ?? {};

所以你总是会解构一个对象