how to use switchMap to cancel pending http requests and taking the last subscribe only?

Question

i tried canceling pending http request using subscription.unsubsribe like this:

getAgentList(pageNumber: number, filter: string): any {
   let requestUrl: s         


        

Answer 1

basic example:

export class MyComponent{
    private $filter: Subject = new Subject();

    constructor(){
        this.$filter
          .switchMap(filter => this.backEndCommService.getData(filter + this.baseUrl)
          .subscribe(res => {//do something})
    }

    getAgentList(filterValue: string){
        this.$filter.next(filterValue);
    }

}

To use switchmap to cancel previous request we need a hot observable which outputs our filter value. We use a subject for that. Everytime we get a new value from somewhere? we push it to the subject.