Improving the readability of Angular and RxJS code

I'm new to RxJs and angular and was wondering if there's a way to make the following code simpler while retaining its functionality. Is there room for improvement or is this as good as it gets?

private configureDataStreams() {

let params$ = this.params$.pipe(debounceTime(300));
this.user$
  .pipe(
    mergeMap(user =>
      from(this.loadPosts(user)).pipe(map(posts => ({ user, posts })))
    ),
    combineLatest(this.dates$, params$),
    switchMap(({user, posts}, dates, params) =>
      from(
        this.loadData(dates.date, dates.endDate, user, posts, params)
      ).pipe(map(data => ({ dates, data })))
    )
  )
  .subscribe(({ dates, data }) => this.displayFetchedData(data, dates));

this.paramsSubject.next(this.params);

}

Answer №1

If you want to enhance the readability of your code, consider implementing something like the following:

let params$ = this.params$.pipe(debounceTime(300));
let userPosts$ = this.user$
  .pipe(
    mergeMap(user =>
      from(this.loadPosts(user)).pipe(map(posts => ({ user, posts })))
    ),
  );

combineLatest(userPosts$, this.dates$, params$)
.pipe(
    switchMap(([{ user, posts }, dates, params]) =>
      from(
        this.loadData(dates.date, dates.endDate, user, posts, params)
      ).pipe(map(data => ({ dates, data })))
    )
)
.subscribe(({ dates, data }) => this.displayData(data, dates));

This approach uses the combineLatest function instead of the deprecated combineLatest operator found in RxJs version 6.

However, there are a few aspects that appear unclear. For example, the use of the from function with this.loadPosts(user) may be questionable. Typically, from accepts an iterable, returning a stream that emits elements individually - does loadPosts return such an iterable?

These inquiries are made to suggest that revisiting the structure of the chain could potentially lead to further improvements in readability.

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