Rxjs catchError 原因 TypeScript 类型错误

Question

我有一个来自 Angular 的例子。 有两个接口。 一个将status定义为字符串。 第二个定义status值。 问题出在后一个，因为catchError function 没有返回正确的类型：

export interface ThisInterfaceIsOk {
    status: string;
}


export interface ThisInterfaceCausesProblem {
    status: "OK" | "PROBLEM";
}


@Injectable({
    providedIn: 'root'
})
export class RegisterService {

    constructor(private httpClient: HttpClient) {
    }


    public registerValid(): Observable<ThisInterfaceIsOk> {
        return this.httpClient.get('http://example.com/api').pipe(
            map(response => response as ThisInterfaceIsOk),
            catchError(() => of({status: "WHATEVER"}))
        );
    }

    public registerInvalid(): Observable<ThisInterfaceCausesProblem> {
        return this.httpClient.get('http://example.com/api').pipe(
            map(respone => respone as ThisInterfaceCausesProblem),
            catchError(() => of({status: "OK"}))
        );
    }
}

错误就像TS2322 Type Observable<ThisInterfaceCausesProblem|{status: string}> is not assignable to type Observable<ThisInterfaceCausesProblem>但我真的不明白为什么。

Answer 1

我相信catchError(() => of({status: "OK"}))给出的返回类型为{ status: string } 。 尝试用这个替换它： catchError(() => of({status: "OK" as const}))