Tap Operator
Rocket.tap — Functiontap(tapFn::F) where { F <: Function }Creates a tap operator, which performs a side effect for every emission on the source Observable, but return an Observable that is identical to the source.
Arguments
tapFn::Function: side-effect tap function with(data) -> Nothingsignature
Producing
Stream of type <: Subscribable{L} where L refers to type of source stream
Examples
using Rocket
source = from([ 1, 2, 3 ])
subscribe!(source |> tap((d) -> println("In tap: $d")), logger())
;
# output
In tap: 1
[LogActor] Data: 1
In tap: 2
[LogActor] Data: 2
In tap: 3
[LogActor] Data: 3
[LogActor] Completed
See also: tap_on_subscribe, tap_on_complete, logger
Description
Returns an Observable that resembles the source Observable, but modifies it so that the provided Observer is called to perform a side effect for every value emitted by the source.
This operator is useful for debugging your Observables, verifying correct values, or performing other side effects.
Note: this operator differs from a subscribe on the Observable. If the Observable returned by tap is not subscribed, the side effects specified by the Observer will never happen. tap therefore simply spies on existing execution, it does not trigger an execution to happen like subscribe does.