Sequential subscription to an array of observables

Question

Here, I've used forkJoin from rxjs to subscribe to an array of observables parallelly. But I want to subscribe to them one by one, What will be the best solution?

Below is my code :

var observables = [];

Observable.forkJoin(observables)
    .subscribe(() => {
        this.msgs = [];
        this.msgs.push({
            severity: 'success',
            summary: 'Saved Successfully'
        });
        this.onSaveComplete();
    }, (error: any) => this.errorMessage = <any>error);
}, (error: any) => this.errorMessage = <any>error);

Answer 1

Alternate of forkJoin means you need to subscribe to the array of observables sequencially. mergeand concat are the ways to go in this case. In your case, modify your code and use a spread operator at the very beginning of your array of observables when using mergeand concat.

var observables = [];
Observable.concat(...observables)
            .subscribe(() => {
                this.msgs = [];
                this.msgs.push({
                    severity: 'success',
                    summary: 'Saved Successfully'
                });
                this.onSaveComplete();
            }, (error: any) => this.errorMessage = <any>error);
    }, (error: any) => this.errorMessage = <any>error);