RxJS：在每次并行HTTP请求返回时更新客户端

Question

Goal: Run a number of async http requests in parallel using RxJS and fire callback after each request is returned.

For example:

getSomeData() {
    Observable.forkJoin(
        this.http.get('/somethingOne.json').map((res:Response) => res.json()),
        this.http.get('/somethingTwo.json').map((res:Response) => res.json())
    ).subscribe(
      data => {
        this.somethingOne = data[0]
        this.somethingTwo = data[1]
      },
      err => console.error(err)
    );
}

The above code will run the http.get requests in parallel and map the response to json, but on each http response I want a function I created to be called. Is there any way to pass a callback function to the http requests that are passed to the forkJoin method?

Answer 1

Would that work? Just executing your function in the body of your current selector function. (There might be some syntax errors here, as I don't use ES6). Included two versions depending on how you want to use that function, but the idea is clear : use your map selector function to run any logic you want.

getSomeData() {
    Observable.forkJoin(
        this.http.get('/somethingOne.json').map((res:Response) => {myFunction(res); return res.json()}),
        this.http.get('/somethingTwo.json').map((res:Response) => myOtherFunction(res.json()))
    ).subscribe(
      data => {
        this.somethingOne = data[0]
        this.somethingTwo = data[1]
      },
      err => console.error(err)
    );
}