问题描述
{ "success": true,"result": {} } // on success
{ "success": false,"message": "nope!" } // on failure
我尝试像这样创建替代类型:
interface ResultSuccess<T> {
success: true;
result: T;
}
interface ErrorMessage {
success: false;
message: string;
}
type Maybe<T> = ResultSuccess<T> | ErrorMessage;
function HandleAPICall(response: Maybe<APIResult>) {
if (response.success) {
DoSomething(response.result);
} else {
console.log(response.message);
}
}
但是在 console.log
语句中,我收到如下错误:
Error TS2339 (TS) Property 'message' does not exist on type 'Maybe<APIResult>'.
Property 'message' does not exist on type 'ResultSuccess<number>'.
\maybe.ts 15 Active
如何从 Maybe 获取 ErrorMessage?
解决方法
您需要在您的 strictNullChecks
中启用 tsconfig.json
(docs) 才能使布尔属性的可区分联合工作。