observables^(1/0)

Organize subscription chains with pipes

Often, two or more observables depend upon one another for execution. This can lead to chained subscriptions. Take this real-world example: this.openInvalidPeriodDialog$(dialog).subscribe(dialog => { dialog.afterClosed().subscribe(jumpToLatestPeriod => { if (jumpToLatestPeriod) { this.periodService.getLatestPeriod().subscribe(latestPeriod => { this.analysisService.getPreliminaryPeriodId$(federalReserveId, analysisId, latestPeriod.id) .subscribe(periodId => this.sessionService.setQualitativePeriod(periodId ?? latestPeriod.id)) }); } }); }); The multiple subscribes() might be written in a more descriptive chain with a pipe and use of switchMap() and filter(). this.openInvalidPeriodDialog$(rejectionDialog) .pipe( switchMap(invalidPeriodDialog => invalidPeriodDialog.afterClosed()), filter(jumpToLatestPeriod => jumpToLatestPeriod), switchMap(() => this.…