RxJS Observable 用新数据替换流

Question

我有一个服务，它会在初始化时更新 observable 的数据，然后在 http 搜索时更新。

使用 next() 将记录添加到 observable 中的数组中，但是我将如何用新集合替换这些记录？

search.service.ts

 private searchSource = new BehaviorSubject<any>(this.getInitialCollections());

    public currentState = this.searchSource.asObservable();

    public getInitialCollections() {
        return this.apiService.post(this.searchApi)
            .subscribe(data => this.changeSubject(data));
    }

    public search(phrase: string) {
        return this.apiService.post(this.searchApi, { phrase: phrase })
            .subscribe(data => this.changeSubject(data));
    }

    private changeSubject(results: object) {
        this.readCollectionResult(results).map(data => this.searchSource.next(data));
    }

    private readCollectionResult(result: any): Asset[] {
        return (result && result.data) ? result.data.map(asset => asset) : [];
    }

组件.ts

export class SearchDataSet {
    /** Stream that emits whenever the data has been modified. */
    dataChange: BehaviorSubject<Asset[]> = new BehaviorSubject<Asset[]>([]);
    get data(): Asset[] { return this.dataChange.value; }

    constructor(
        private _searchService: SearchService
    ) {
        this.initialize();
    }

    records = this.data.slice();

    initialize() {
        this._searchService.currentState
            .subscribe(item => !item.id ? null : this.addRecord(item));
    }

    /** Adds a new asset to the database. */
    addRecord(item: object) {
        this.records.push(item);
        this.dataChange.next(this.records);
    }
}

Answer 1

'使用 next() 将记录添加到 observable 中的数组'

实际上，由于 searchSource 是一个 BehaviorSubject，它只能保存一个值，所以 searchSource.next(data) 将 searchSource 的当前内容替换为数据。

您可能需要其他方法

private addToSubject(results: object) {
  this.searchSource.subscribe(current => {
    const assets = this.readCollectionResult(results);
    this.searchSource.next(current.concat(assets));
  });
}