Switch is a higher-order operator, so it takes as input a sequence of observable sequences. At any moment Switch is subscribed exclusively to the latest source sequence. As soon as a new sequence is emitted by the outer observable, it cancels subscription to the previous sequence and subscribes to the new sequence.

The resulting sequence will terminate successfully when the outer sequence has terminated successfully, and the currently active sequence (if any) also terminates successfully. It will terminate exceptionally if any of the sequences produces an error.

Switch is useful to model interruptible states, for example when transitioning between different modes of a state-machine, or switching between different video channels on demand.

Examples

Use Switch to switch to a new observable sequence as soon as it is created.

Related Operators

Use Amb instead to propagate the first observable sequence to emit a notification.