NG2-使用DataLoader的管理模板图表

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable, of } from 'rxjs';
import { catchError, map } from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class ChartDataService {
  private cache = new Map<string, any>();

  constructor(private http: HttpClient) {}

  getChartData(chartId: string): Observable<any> {
    if (this.cache.has(chartId)) {
      return of(this.cache.get(chartId));
    }

    return this.http.get(`/api/charts/${chartId}`).pipe(
      map(data => {
        this.cache.set(chartId, data);
        return data;
      }),
      catchError(error => {
        console.error('Error fetching chart data:', error);
        return of(null); // 返回空数据或错误信息
      })
    );
  }
}