CODEWITHSUNDEEP
angularrxjs
LastTribunal
LastTribunal

Reputation: 1

Angular 4, awaiting something before http call

I have an http service with a method like this:

  get(url): Promise<Object> {
    //await something here before next line
        return this.httpClient.get(url)
           .map((res) => {
                   return res as Object
                })
              .toPromise();

I need to call a method that eventually perform some object updates. How do I make the above method wait until the other is finished?

Upvotes: 1

Views: 811

Answers (2)

LastTribunal
LastTribunal

Reputation: 1

This is how I solved it:

    get(url): Promise<Object> {
           return this.sendRequest(url, 'get', '')
                   .map((res) => {
                        return res as Object
                      })
                   .toPromise();
        }

    sendRequest(url, type, body): Observable<any> {
           return this.adalService.acquireToken()
               .flatMap((token: string) => {
//I am not using the result of the flatmap, only exploiting it to ensure resolution, httpClient is being intercepted with the updated values
                  return this.httpClient[type](url, body)
           });
    }

Upvotes: 0

Vamshi
Vamshi

Reputation: 9330

This can be done many ways. One of them is forkJoin ( which is similar to promise.all)

// parallel method you want to execute , let this return an observable
doSomething(){
    return this.http.get('token'.... );
}

get(url): Promise<Object> {
   return Observable.forkJoin([doSomething(),this.httpClient.get(url)])
       .map((res) => { //res is an array with both outputs
            // we are only concerned with second response 
            return res[1] as Object; 
        })
        .toPromise();

Upvotes: 2

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