Angular: accomplish cascading requests to achieve desired outcomes

Question

Angular: accomplish cascading requests to achieve desired outcomes

While exploring Angular rxjs operators, I came across a scenario where I need to send requests to the server that depend on each other. Currently, I have a modal window open and during the ngOnInit lifecycle hook, multiple requests are being sent, some of which are interconnected. However, I have not utilized any rxjs operators in these requests.

For example:

getMyCompanyDetails(){
 this.companyService.getCompany('my company name').subscribe(
  data => {
  // Implement logic here that depends on the second request
 }
}

My objective is to sequentially send requests that are dependent on each other, where the second request waits for the first one to complete. I have come across different approaches like switchMap, concatMap, etc., but I am facing challenges in implementing them. I would greatly appreciate your guidance on the best pattern or solution to handle this scenario effectively. Thank you!

angular typescript rxjs httprequest rxjs-pipeable-operators

Answer 1

Answer №1

If you want to handle the response using the switchMap operator, be prepared to return a new observable in the process. Utilize this technique to generate an observable based on the result of your 'getCompany' call. Subsequently, you can subscribe to the new observable to access its response.

fetchMyCompanyDetails(){
 this.companyService.getCompany('my company name').pipe(switchMap((data) => { 
   if (data) {
     return someObservable;
   } 

   return otherObservable;
 })).subscribe((resultOfInnerObs) => { /* perform an action */ })

For further insights and practical demonstrations, explore the resources and examples available at https://www.learnrxjs.io/learn-rxjs/operators/transformation/switchmap

Answer 2

If you want to handle the response using the switchMap operator, be prepared to return a new observable in the process. Utilize this technique to generate an observable based on the result of your 'getCompany' call. Subsequently, you can subscribe to the new observable to access its response.

fetchMyCompanyDetails(){
 this.companyService.getCompany('my company name').pipe(switchMap((data) => { 
   if (data) {
     return someObservable;
   } 

   return otherObservable;
 })).subscribe((resultOfInnerObs) => { /* perform an action */ })

For further insights and practical demonstrations, explore the resources and examples available at https://www.learnrxjs.io/learn-rxjs/operators/transformation/switchmap

Angular: accomplish cascading requests to achieve desired outcomes

Answer №1

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