问题描述
当服务发出新的到期时间时,我试图“重置”计时器。我覆盖了可观察的东西。我不确定是否应该“垃圾收集”可观察到的东西,或者是否有更好的方法“重置”计时器。
此代码可以正常工作,但我不确定这是否是最佳做法
const openModal = () => {
if (this.sessionModal === null) {
this.sessionModal = this.modalService.open(SessionModalComponent,{size: 'sm',backdrop: 'static',keyboard: false});
this.sessionModal.result.then(() => this.sessionModal = null);
}
};
this.expiresAt = authService.expiresAt;
if (this.expiresAt !== null) {
this.sessionTimerSubscription
= timer(this.expiresAt.getTime() - (new Date()).getTime() - this.sessionModalOffset).subscribe(openModal);
authService.expiresAt$.subscribe((expiresAt) => {
this.expiresAt = expiresAt;
this.sessionTimerSubscription.unsubscribe();
this.sessionTimerSubscription
= timer(this.expiresAt.getTime() - (new Date()).getTime() - this.sessionModalOffset).subscribe(openModal);
});
}
解决方法
不太清楚您想要什么,但这似乎就是您想要做的:
this.expiresAt = authService.expiresAt;
if (this.expiresAt !== null) {
// when the signal emits
authService.expiresAt$.pipe(
startWith(this.expiresAt),// starting with the current value
tap(expiresAt => this.expiresAt = expiresAt),// set the state (if you must?)
switchMap(expiresAt => // switch into a new timer
timer(expiresAt.getTime() - (new Date()).getTime() - this.sessionModalOffset)
)
).subscribe(openModal); // subscribe the modal?
}
嵌套在订阅中的订阅是一种不好的做法,并且会导致代码混乱。使用运算符根据需要合并流。