可观察的数组，找到值的索引 [英] Observable of array, find index of value

问题描述

我正在编写一个 Angular 应用，它从一个服务中获取一系列商店，作为一个 Observable.

I'm writing an Angular app that gets a selection of stores from a service, as an Observable.

当用户单击地图上的标记时，我想获取位于 Observable 内的数组中商店的索引.

When the user clicks a marker on the map, I want to get the index of the store in the array that lives inside the Observable.

stores: Observable<Store[]>;

ngOnInit() {
    this.stores = http.get<Store[]>('URL');
}

onMarkerClick(event) {
   const geopoint = event.geopoint;
   //How can I get the index where store.geopoint === event.geopoint?
}

推荐答案

用于从数组中过滤商店:

For filtering the stores from the array you do:

this.storesCollection.filter(store => store.geopoint === event.geopoint); // -1 if not found

为了将 Observable 转换为数组，使用 map:

And for transforming the Observable to an Array use map:

this.stores$.map((stores: Stores[]) => this.storesCollection = stores)

您不需要执行 subscribe() 因为 http 返回一个热门的 observable，无论是否有订阅者，它总是会触发

You don't need to do subscribe() because http returns a hot observable, always firing regardless of there being a subscriber or not

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