Sending two http request one after another-CodePudding

I have 2 api calls which i want to send one after the other. I need a response of the 1st one to send the 2nd api request, but i also need the data from first call. Looks like switchMap is the way to go, atm it looks like this:

this.apiCall1().pipe(switchMap(res1 => this.apiCall2(res.data))).subscribe(res => ...)

but i need to assign the res1.differentData to a variable which seems impossible with switchMap. Or maybe im just missing some syntax.

CodePudding user response：

I suggest you to just reemit the value coming from apiCall1() and use forkJoin to get both values at the end:

this.apiCall1().pipe(
  switchMap(res => forkJoin(
    [of(res), this.apiCall2(res)]
  ))).subscribe(console.log)

this way you receive an array containing two elements (the results of both calls) at the end.

CodePudding user response：

You can also use map to the inner call to include all or part of the response from outer (usually used in a typical element details)

this.apiCall1().pipe(
  switchMap(res1 => this.apiCall2(res1).pipe(
           map(res2=>({res1:res1,res2:res2})))
  )

CodePudding user response：

Without running the code myself, here is my take.

Possibly break-out your callback function:

let res1Stored;

this
  .apiCall1()
  .pipe(switchMap(res1 => {
    res1Stored = res1.differentData;
    return this.apiCall2(res.data);
  }))
  .subscribe(res => ...)

Hope this helps.