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I was originally searching how to return several actions in a ngrx effect, and found I need to return an array of actions.
Then I noticed that returning a simple array in the switchMap works as fine as returning an observable created from this array.
For example:

timer(1000).pipe(switchMap(val => from([val, val + 1)])).subscribe(val => console.log(val));

timer(1000).pipe(switchMap(val => [val, val + 1])).subscribe(val => console.log(val));

I expect the first to work and think it is the correct syntax.
I don't expect the second to work but it actually does and I would like to understand why.
Thanks,

Vash42
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1 Answers1

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Because switchMap, among other flattening-operators (mergeMap, exhaustMap, ...), takes an ObservableLike as the return type of its projection function.

An ObservableLike can be Observable, Promise or Array. If you provide an array, it is converted into a stream of its items - basically the same as if you had used from.

ggradnig
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