First operator

first(; default = nothing)

Creates a first operator, which returns an Observable that emits only the first value emitted by the source Observable. Sends FirstNotFoundException error message if a given source completes without emitting a single value.

Arguments

• default: an optional default value to provide if no values were emitted

Producing

Stream of type <: Subscribable{L} where L refers to type of source stream

Examples

using Rocket

source       = from(1:100)
subscription = subscribe!(source |> first(), logger())
;

# output

[LogActor] Data: 1
[LogActor] Completed

See also: take, logger