[英]Angular firebase subscribe function called twice
我正在嘗試使用 mapbox-gl 在地圖中的標記上的彈出窗口上制作按鈕。 這些按鈕允許訂閱/取消訂閱一個地方。 但是當我點擊它們時,我看到 subscribe 函數被調用了兩次並導致結果錯誤。
這是下面的第三個函數。
loadPlaces() {
this.placeService.getAll().subscribe(
(places: Place[]) => {
this.places = places;
this.places.forEach((place: Place) => {
const popup = new mapboxgl.Popup({ offset: 25 })
.setDOMContent(this.setPopUpContent(place));
new mapboxgl.Marker({color: 'red'})
.setLngLat(place.coordinates)
.setPopup(popup)
.addTo(this.map);
});
}
);
}
setPopUpContent(place: Place) {
const popupContent = document.createElement('div');
const title = document.createElement('p');
title.innerText = place.name;
const button = document.createElement('button');
button.innerText = 'Subscribe';
this.setSubscribeButton(place, button);
popupContent.append(title, button);
return popupContent;
}
setSubscribeButton(place: Place, button: any) {
this.placeSubscriptionService.isSubscribed(this.authService.getCurrentUser().uid, place.id).subscribe(subscribed => {
console.log(subscribed);
if (!subscribed) {
button.innerHTML = 'Subscribe';
button.onclick = () => {
this.subscribe(place);
};
} else {
button.innerHTML = 'Unsubscribe';
button.onclick = () => {
this.unsubscribe(place);
};
}
});
}
subscribe(place: Place) {
const placeSubscription: any = {
userId: this.authService.getCurrentUser().uid,
placeId: place.id
};
this.placeSubscriptionService.create(placeSubscription);
}
unsubscribe(place) {
this.placeSubscriptionService.getSubscriptionId(this.authService.getCurrentUser().uid, place.id).subscribe(subscriptionId => {
this.placeSubscriptionService.delete(subscriptionId);
});
}
這里是服務中的代碼,用於檢查用戶是否訂閱了 firestore 上的位置:
isSubscribed(userId: string, placeId: string): Observable<boolean> {
return this.firestore.collection<PlaceSubscription>(this.collectionName, ref => ref
.where('userId', '==', userId)
.where('placeId', '==', placeId))
.snapshotChanges()
.pipe(map(placeSubscriptions => {
const placeSubscription = placeSubscriptions[0];
if (placeSubscription) {
return true;
} else {
return false;
}
}));
}
當我單擊訂閱該地點的按鈕時顯示函數 isSubscribed 的結果時,它返回兩次“true”。 在點擊按鈕取消訂閱一次后,當我重新訂閱時,它返回兩次真,最后一次假。 所以我不能再訂閱這個地方,因為它直接進入真假。
有什么我做錯了嗎?
非常感謝您的寶貴時間。
編輯 :
let subscription: Subscription;
const popup = new mapboxgl.Popup({ offset: 25 })
.on('open', () => {
console.log('open');
subscription = this.placeSubscriptionService.isSubscribed(this.authService.getCurrentUser().uid, place.id)
.pipe(first()).subscribe(
subscribed => {
console.log(subscribed);
popup.setDOMContent(this.setPopUpContent(place, subscribed));
});
})
.on('close', () => {
if (subscription) {
subscription.unsubscribe();
}
});
setPopUpContent(place: Place, subscribed: boolean) {
const popupContent = document.createElement('div');
const title = document.createElement('p');
title.innerText = place.name;
const button = document.createElement('button');
button.innerText = 'Subscribe';
if (subscribed) {
button.innerText = 'Unsubscribe';
button.onclick = () => {
this.unsubscribe(place);
};
} else {
button.innerText = 'Subscribe';
button.onclick = () => {
this.subscribe(place);
};
}
popupContent.append(title, button);
return popupContent;
}
這里涉及的代碼很多,(如果你能提供最少的可重現代碼,人們可以更好地幫助你)
無論如何,我認為有問題的是,您永遠不會取消訂閱 observable 並且與您調用的loadPlaces
一樣多,它會調用越來越多
一種解決方法是下面的代碼,因為first()
導致您的訂閱結束
this.placeService.getAll()
.pipe(
first()
)
.subscribe(
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