当用户id更改时,订阅将随机运行。有时,我不这样做。UsRID变量来自下拉选择器(选择库)。
即使userid是唯一更改的流,订阅也不应该一直运行吗?
有没有什么明显的迹象表明我正在崩溃或做错了?

this.singleUserControl.valueChanges
    .mergeMap((userId: number) => {
        this.router.navigate([ '/r', 'company-admin', 'user-claims', userId.toString() ]);
        this.userRoles = [];
        this.claims = [];
        const userRolesObserv: Observable<Array<RoleWithClaims>> =
            this.claimsService.getUserRoles(userId)
                .mergeMap((roles: Array<Role>) => {
                    const roleObservables = [];

                    for (const role of roles) {
                        roleObservables.push(this.claimsService.getClaimsForRole(role.id)
                            .mapTo(claims => ({
                                role: role,
                                claims: claims,
                            } as RoleWithClaims)));
                    }

                    return forkJoin(roleObservables);
                });

        return forkJoin([
            Observable.of(userId),
            userRolesObserv,
            this.claimsService.getAllClaimsForUser(userId),
        ]);
    })
    .subscribe((data: [ number, Array<RoleWithClaims>, Array<Claim>]) => {
        this.userSelectedId = data[0];
        this.userRoles = data[1]
        this.claims = data[2];
    }, (error) => {
        console.log(error);
    });

最佳答案

尝试这样做:

return (roleObservables.length) ? forkJoin(roleObservables) : Observable.of([]);

forkjoin不会以空数组发出,因此在这段代码中,不会对没有关联角色的任何用户id执行订阅。
在我所有的RX项目中,我都有一个实用功能:
emptyJoin(obs: Observable<any>[]): Observable<any[]> => (obs.length) ? forkJoin(obs) : Observable.of([]);

07-24 09:50
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