Rx.Observable.if(condition, thenSource, [elseSource])

Determines whether an observable collection contains values.

Arguments

1. condition (Function): The condition which determines if the thenSource or elseSource will be run.
2. thenSource (Observable): thenSource The observable sequence that will be run if the condition function returns true.
3. [elseSource] (Observable|Scheduler): The observable sequence that will be run if the condition function returns false. If this is not provided, it defaults to Rx.Observabe.Empty with the specified scheduler.

Returns

(Observable): The generated sequence.

Example

This uses and only then source

The next example uses an elseSource