[英]Angular better way to clear subscriptions
有很多方法可以在一個組件中有效地處理多個訂閱,我這里有兩種方法,想知道哪種方法更有效,為什么?
第 1 步:創建數組
private subscriptionArray: Subscription[];
第 2 步:向數組添加訂閱
this.subscriptionArray.push(this._storeManagementHttp.createStore(newStore).subscribe(resp => {
this._toast.success('New store created');
}));
步驟 3:迭代每個訂閱和取消訂閱
this.subscriptionArray.forEach(subs => subs.unsubscribe());
第 1 步:創建新訂閱
private subscriptions = new Subscription();
第 2 步:添加訂閱
this.subscriptions.add(this._storeManagementHttp.createStore(newStore).subscribe(resp => {
this._toast.success('New store created');
this._router.navigate(['/store-management']);
}));
Step3:清除訂閱
this.subscriptions.unsubscribe();
你也可以這個,在這種情況下你不需要運行循環
private destroy$ = new Subject();
myservice.megohd().pipe(takeUntil(destroy$)).subscribe();
ngOnDestroy() {
this.destroy$.next();
this.destroy$.complete();
}
在這里閱讀( https://www.learnrxjs.io/operators/filtering/takeuntil.html )
您還有第三個選項,即自定義 RxJS 運算符。
我創建了一個,發現Netanel Basal也找到了它,所以我會給出他的干凈代碼。
您可以安裝UntilDestroyed或使用代碼:
function isFunction(value) {
return typeof value === 'function';
}
export const untilDestroyed = (
componentInstance,
destroyMethodName = 'ngOnDestroy'
) => <T>(source: Observable<T>) => {
const originalDestroy = componentInstance[destroyMethodName];
if (isFunction(originalDestroy) === false) {
throw new Error(
`${
componentInstance.constructor.name
} is using untilDestroyed but doesn't implement ${destroyMethodName}`
);
}
if (!componentInstance['__takeUntilDestroy']) {
componentInstance['__takeUntilDestroy'] = new Subject();
componentInstance[destroyMethodName] = function() {
isFunction(originalDestroy) && originalDestroy.apply(this, arguments);
componentInstance['__takeUntilDestroy'].next(true);
componentInstance['__takeUntilDestroy'].complete();
};
}
return source.pipe(takeUntil<T>(componentInstance['__takeUntilDestroy']));
};
然后你的訂閱變成
this.myService.subject.pipe(untilDestroyed(this)).subscribe(...);
請注意,由於 AOT 編譯,您必須編寫一個ngOnDestroy
方法,否則操作員無法從頭開始創建它。
有更好、更簡潔的解決方案:Ward Bell 的https://www.npmjs.com/package/subsink
export class SomeComponent implements OnDestroy {
private subs = new SubSink();
...
this.subs.sink = observable$.subscribe(...);
this.subs.sink = observable$.subscribe(...);
this.subs.sink = observable$.subscribe(...);
...
// Unsubscribe when the component dies
ngOnDestroy() {
this.subs.unsubscribe();
}
}
盡管我會盡可能避免使用上述所有方法並使用async
'pipe,但您提供了很好的答案,即允許 Angular 進行訂閱和取消訂閱。
讓我們考慮一些 Observables 說 5 observables
observale1$: Observable<IDataDto1>;
observale2$: Observable<IDataDto2>;
observale3$: Observable<IDataDto3>;
observale4$: Observable<IDataDto4>;
observale5$: Observable<IDataDto5>;
為了避免訂閱所有這些,我們可以創建一個單獨的Observable
比如說v$
import { forkJoin } from 'rxjs';
v$ = forkJoin({
observale1: observale1$,
observale2: observale2$,
observale3: observale3$,
observale4: observale4$,
observale5: observale5$
});
有了上面的內容,我們可以將component.html包裝在*ngIf
中,並允許 Angular 自動訂閱和取消訂閱
<ng-container *ngIf='v$ | async as v'>
<!-- Your html code here -->
</ng-container>
方法 2 因為Subscription.unsubscribe()
不僅僅是看似取消訂閱, 請在此處查看其源代碼。
例如
class SomeClass implements OnInit, OnDestroy { {
// Setup your subscriptions
private subscriptions = new Subscription();
// Example Observable service
constructor(private someService: SomeService) {}
ngOnInit(): void {
this.subscriptions.add(this.someService.getStuff());
// ...
this.subscriptions.add(/* etc */);
}
ngOnDestroy() {
this.subscriptions.unsubscribe();
}
}
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