取消所有挂起的请求angular4

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent } from '@angular/common/http';
import { Observable } from 'rxjs';
import { finalize } from 'rxjs/operators';

@Injectable()
export class CancelPendingRequestsInterceptor implements HttpInterceptor {
  private pendingRequests: Array<Observable<any>> = [];

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    // 取消挂起的请求
    this.cancelPendingRequests();

    // 将当前请求添加到挂起请求列表
    const pendingRequest = next.handle(request).pipe(
      finalize(() => {
        const index = this.pendingRequests.indexOf(pendingRequest);
        if (index !== -1) {
          this.pendingRequests.splice(index, 1);
        }
      })
    );
    this.pendingRequests.push(pendingRequest);

    return pendingRequest;
  }

  private cancelPendingRequests(): void {
    this.pendingRequests.forEach((pendingRequest) => {
      pendingRequest.unsubscribe();
    });
    this.pendingRequests = [];
  }
}

import { NgModule } from '@angular/core';
import { HTTP_INTERCEPTORS } from '@angular/common/http';
import { CancelPendingRequestsInterceptor } from './cancel-pending-requests.interceptor';

@NgModule({
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: CancelPendingRequestsInterceptor,
      multi: true
    }
  ]
})
export class AppModule { }