# NAME RxPerl - an implementation of Reactive Extensions / rxjs for Perl # SYNOPSIS # one of...: > cpanm RxPerl::AnyEvent > cpanm RxPerl::IOAsync > cpanm RxPerl::Mojo # ..and then (if installed RxPerl::Mojo, for example): use RxPerl::Mojo 'rx_interval', 'op_take'; # or ':all' use Mojo::IOLoop; rx_interval(1.4)->pipe( op_take(5), )->subscribe(sub { say "next: ", $_[0] }); Mojo::IOLoop->start; # NOTE You probably want to install one of the three adapter modules for your project instead of this one: [RxPerl::AnyEvent](https://metacpan.org/pod/RxPerl%3A%3AAnyEvent), [RxPerl::IOAsync](https://metacpan.org/pod/RxPerl%3A%3AIOAsync) or [RxPerl::Mojo](https://metacpan.org/pod/RxPerl%3A%3AMojo). Each of these three modules adapts RxPerl to one of three event interfaces available in Perl ([AnyEvent](https://metacpan.org/pod/AnyEvent), [IO::Async](https://metacpan.org/pod/IO%3A%3AAsync) and [Mojo::IOLoop](https://metacpan.org/pod/Mojo%3A%3AIOLoop)), so pick the one that corresponds to the event interface that your app uses. The documentation in this POD applies to all three adapter modules as well. # DESCRIPTION This module is an implementation of [Reactive Extensions](http://reactivex.io/) in Perl. It replicates the behavior of [rxjs 6](https://www.npmjs.com/package/rxjs) which is the JavaScript implementation of ReactiveX. Currently 54 of the 100+ operators in rxjs are implemented in this module. # EXPORTABLE FUNCTIONS The code samples in this section assume `$observer` has been set to: $observer = { next => sub {say "next: ", $_[0]}, error => sub {say "error: ", $_[0]}, complete => sub {say "complete"}, }; ## OBSERVABLE CREATION OPERATORS Creation operators create and return an _observable_. They are usually unicast, which means that when an ["rx\_interval"](#rx_interval) _observable_ is subscribed to three seperate times there will be three different & distinct recurring intervals. Exceptions to this are with [subjects](#rx_subject) and that any observable can be transformed into a [multicasting](https://www.learnrxjs.io/learn-rxjs/operators/multicasting) one using the ["op\_share"](#op_share) pipeable operator (or by other similar operators). The following list is the currently implemented creation operators with links to relevant rxjs documentation (which should apply to RxPerl too). - rx\_behavior\_subject [https://rxjs.dev/api/index/class/BehaviorSubject](https://rxjs.dev/api/index/class/BehaviorSubject) # 10, 20, 30, complete my $b_s = rx_behavior_subject->new(10); $b_s->subscribe($observer); $b_s->next(20); $b_s->next(30); $b_s->complete; # 20, 30, complete my $b_s = rx_behavior_subject->new(10); $b_s->next(20); $b_s->subscribe($observer); $b_s->next(30); $b_s->complete; - rx\_combine\_latest [https://rxjs.dev/api/index/function/combineLatest](https://rxjs.dev/api/index/function/combineLatest) # [0, 0], [0, 1], [1, 1], [1, 2], [1, 3], ... rx_combine_latest([ rx_interval(1), rx_interval(0.7), ])->subscribe($observer); - rx\_concat [https://rxjs.dev/api/index/function/concat](https://rxjs.dev/api/index/function/concat) # 10, 20, 30, 10, 20, 30, 40, complete rx_concat( rx_of(10, 20, 30), rx_of(10, 20, 30, 40), )->subscribe($observer); - rx\_defer [https://rxjs.dev/api/index/function/defer](https://rxjs.dev/api/index/function/defer) # Suppose "int rand 10" here evaluates to 7. Then if after 7 seconds $special_var holds a true value, # output will be: 0, 1, 2, 3, 4, 5, 6, 10, 20, 30, complete, otherwise it will be: # 0, 1, 2, 3, 4, 5, 6, 40, 50, 60, complete. rx_concat( rx_interval(1)->pipe( op_take(int rand 10) ), rx_defer(sub { return $special_var ? rx_of(10, 20, 30) : rx_of(40, 50, 60) }) )->subscribe($observer); - rx\_EMPTY [https://rxjs.dev/api/index/const/EMPTY](https://rxjs.dev/api/index/const/EMPTY) # complete rx_EMPTY->subscribe($observer); # 10, 20, 30, 40, 50, 60, complete rx_concat( rx_of(10, 20, 30), rx_EMPTY, rx_EMPTY, rx_EMPTY, rx_of(40, 50, 60), )->subscribe($observer); - rx\_fork\_join [https://rxjs.dev/api/index/function/forkJoin](https://rxjs.dev/api/index/function/forkJoin) # [30, 3, 'c'], complete rx_fork_join([ rx_of(10, 20, 30), rx_of(1, 2, 3), rx_of('a', 'b', 'c'), ])->subscribe($observer); # {x => 30, y => 3, z => 'c'}, complete rx_fork_join({ x => rx_of(10, 20, 30), y => rx_of(1, 2, 3), z => rx_of('a', 'b', 'c'), })->subscribe($observer); - rx\_from [https://rxjs.dev/api/index/function/from](https://rxjs.dev/api/index/function/from) Currently, only arrayrefs, promises, Futures, observables and strings are allowed as argument to this function. # 10, 20, 30, complete rx_from([10, 20, 30])->subscribe($observer); - rx\_from\_event [https://rxjs.dev/api/index/function/fromEvent](https://rxjs.dev/api/index/function/fromEvent) Currently, only instances of the [Mojo::EventEmitter](https://metacpan.org/pod/Mojo%3A%3AEventEmitter) class are allowed as the first argument to this function. # 4 seconds after Mojolicious hypnotoad is gracefully reloaded, websocket # connection will close sub websocket ($c) { rx_from_event($ioloop, 'finish')->pipe( op_delay(4), )->subscribe({ next => sub { $c->finish }, }); } - rx\_from\_event\_array [https://rxjs.dev/api/index/function/fromEvent](https://rxjs.dev/api/index/function/fromEvent) Similar to: ["rx\_from\_event"](#rx_from_event). Observables may emit at most one value per event, however [Mojo::EventEmitter](https://metacpan.org/pod/Mojo%3A%3AEventEmitter)'s are able to emit more. So this function serves to pack all of them in an arrayref, and emit that as a single value instead. - rx\_interval [https://rxjs.dev/api/index/function/interval](https://rxjs.dev/api/index/function/interval) Works like rxjs's "interval", except the parameter is in seconds instead of ms. # 0, 1, 2, ... every 0.7 seconds rx_interval(0.7)->subscribe($observer); - rx\_merge [https://rxjs.dev/api/index/function/merge](https://rxjs.dev/api/index/function/merge) # 0, 0, 1, 1, 2, 3, 2, 4, 3, ... rx_merge( rx_interval(0.7), rx_interval(1), )->subscribe($observer); - rx\_NEVER [https://rxjs.dev/api/index/const/NEVER](https://rxjs.dev/api/index/const/NEVER) # 10, 20, 30 (and no complete) rx_concat( rx_of(10, 20, 30), rx_NEVER, rx_of(40, 50, 60), )->subscribe($observer); - rx\_observable [https://rxjs.dev/api/index/class/Observable](https://rxjs.dev/api/index/class/Observable) # 0.578, 0.234, 0.678, ... (every 1 second) my $o = rx_observable->new(sub ($subscriber) { # your code goes here Mojo::IOLoop->recurring(1, sub {$subscriber->next(rand())}); }); - rx\_of [https://rxjs.dev/api/index/function/of](https://rxjs.dev/api/index/function/of) # 10, 20, 30, complete rx_of(10, 20, 30)->subscribe($observer); - rx\_partition [https://rxjs.dev/api/index/function/partition](https://rxjs.dev/api/index/function/partition) # 1, 3, 5, 7, 9, 0, 2, 4, 6, 8, complete my $source = rx_interval(1)->pipe( op_take(10) ); my ($o1, $o2) = rx_partition( $source, sub ($value, $index) { $value % 2 == 1 }, ); rx_concat($o1, $o2)->subscribe($observer); - rx\_race [https://rxjs.dev/api/index/function/race](https://rxjs.dev/api/index/function/race) # 0, 10, 20, 30, ... (every 0.7 seconds) rx_race( rx_interval(1)->pipe( op_map(sub {$_[0] * 100}) ), rx_interval(0.7)->pipe( op_map(sub {$_[0] * 10) ), )->subscribe($observer); - rx\_replay\_subject [https://rxjs.dev/api/index/class/ReplaySubject](https://rxjs.dev/api/index/class/ReplaySubject) Works like rxjs's "replaySubject", except the `window_time` parameter is in seconds instead of ms. # 20, 30, 40, 50, complete my $rs = rx_replay_subject(2); $rs->next(10); $rs->next(20); $rs->next(30); $rs->subscribe($observer); $rs->next(40); $rs->next(50); $rs->complete; # or... my $rs = rx_replay_subject(2, 3); # params: buffer_size, window_time - rx\_subject [https://rxjs.dev/api/index/class/Subject](https://rxjs.dev/api/index/class/Subject) # 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, complete my $subject = rx_subject->new; $subject->subscribe($observer); # elsewhere... $subject->next($_) for 1 .. 10; $subject->complete; - rx\_throw\_error [https://rxjs.dev/api/index/function/throwError](https://rxjs.dev/api/index/function/throwError) # 0, 1, 2, 3, error: foo rx_concat( rx_interval(1)->pipe( op_take(4) ), rx_throw_error('foo'), )->subscribe($observer); - rx\_timer [https://rxjs.dev/api/index/function/timer](https://rxjs.dev/api/index/function/timer) Works like rxjs's "timer", except the parameter is in seconds instead of ms. # (pause 10 seconds) 0, complete rx_timer(10)->subscribe($observer); # (pause 10 seconds) 0, 1, 2, 3, ... (every 1 second) rx_timer(10, 1)->subscribe($observer); ## PIPEABLE OPERATORS Pipeable operators (also referred to as "operators") are passed as arguments to the ["pipe"](#pipe) method of observables. Their function is to take an observable, transform it somehow, then (similar to piped shell commands) pass the result of the transformation to the next pipeable operator in the pipe, or return it to the user. The following list is the currently implemented operators, with links to relevant rxjs documentation (which should apply to RxPerl too). - op\_audit\_time [https://rxjs.dev/api/operators/auditTime](https://rxjs.dev/api/operators/auditTime) Works like rxjs's "auditTime", except the parameter is in seconds instead of ms. # 30, complete rx_concat( rx_of(10, 20, 30), rx_EMPTY->pipe( op_delay(5) ), )->pipe( op_audit_time(1), )->subscribe($observer); - op\_buffer\_count [https://rxjs.dev/api/operators/bufferCount](https://rxjs.dev/api/operators/bufferCount) # [10, 20, 30], [40, 50], complete rx_of(10, 20, 30, 40, 50)->pipe( op_buffer_count(3), )->subscribe($observer); # [10, 20, 30], [20, 30, 40], [30, 40, 50], [40, 50], [50], complete rx_of(10, 20, 30, 40, 50)->pipe( op_buffer_count(3, 1), )->subscribe($observer); - op\_catch\_error [https://rxjs.dev/api/operators/catchError](https://rxjs.dev/api/operators/catchError) # foo, foo, foo, complete rx_throw_error('foo')->pipe( op_catch_error(sub ($err, $caught) { rx_of($err, $err, $err) }), )->subscribe($observer); - op\_combine\_latest\_with [https://rxjs.dev/api/operators/combineLatestWith](https://rxjs.dev/api/operators/combineLatestWith) Similar to rx\_combine\_latest, but as a pipeable operator. # [0, 0, -5], [0, 1, -5], [10, 1, -5], [10, 2, -5], [10, 3, -5], [20, 3, -5], ... rx_interval(1)->pipe( op_map(sub { $_ * 10 }), op_combine_latest_with( rx_interval(0.7), rx_of(-5), ), op_take(10), )->subscribe($observer); - op\_concat\_map [https://rxjs.dev/api/operators/concatMap](https://rxjs.dev/api/operators/concatMap) # 0, 1, 2, 0, 1, 2, 0, 1, 2, complete rx_of(10, 20, 30)->pipe( op_concat_map(sub { rx_interval(1)->pipe(op_take(3)), }), )->subscribe($observer); - op\_debounce\_time [https://rxjs.dev/api/operators/debounceTime](https://rxjs.dev/api/operators/debounceTime) Works like rxjs's "debounceTime", except the parameter is in seconds instead of ms. # 3, complete rx_of(1, 2, 3)->pipe( op_debounce_time(0.5), )->subscribe($observer); - op\_delay [https://rxjs.dev/api/operators/delay](https://rxjs.dev/api/operators/delay) Works like rxjs's "delay", except the parameter is in seconds instead of ms. # (pause 11 seconds) 0, 1, 2, 3, ... rx_interval(1)->pipe( op_delay(10) )->subscribe($observer); - op\_distinct\_until\_changed [https://rxjs.dev/api/operators/distinctUntilChanged](https://rxjs.dev/api/operators/distinctUntilChanged) # 10, undef, 20, 30, [], [], complete rx_of(10, 10, undef, undef, 20, 20, 20, 30, 30, [], [])->pipe( op_distinct_until_changed(), )->subscribe($observer); # {name => 'Peter', grade => 'A'}, {name => 'Mary', grade => 'B'}, complete rx_of( {name => 'Peter', grade => 'A'}, {name => 'Peter', grade => 'B'}, {name => 'Mary', grade => 'B'}, {name => 'Mary', grade => 'A'}, )->pipe( op_distinct_until_changed(sub { return $_[0]->{name} eq $_[1]->{name}; }), )->subscribe($observer); - op\_distinct\_until\_key\_changed [https://rxjs.dev/api/operators/distinctUntilKeyChanged](https://rxjs.dev/api/operators/distinctUntilKeyChanged) # {name => 'Peter', grade => 'A'}, {name => 'Mary', grade => 'B'}, complete rx_of( {name => 'Peter', grade => 'A'}, {name => 'Peter', grade => 'B'}, {name => 'Mary', grade => 'B'}, {name => 'Mary', grade => 'A'}, )->pipe( op_distinct_until_key_changed('name'), )->subscribe($observer); - op\_end\_with [https://rxjs.dev/api/operators/endWith](https://rxjs.dev/api/operators/endWith) # 0, 1, 2, 3, 100, 200, complete rx_of(0, 1, 2, 3)->pipe( op_end_with(100, 200), )->subscribe($observer); - op\_exhaust\_map [https://rxjs.dev/api/operators/exhaustMap](https://rxjs.dev/api/operators/exhaustMap) # 0, 1, 2, complete rx_of(10, 20, 30)->pipe( op_exhaust_map(sub { rx_interval(1)->pipe( op_take(3) ); }), )->subscribe($observer); - op\_filter [https://rxjs.dev/api/operators/filter](https://rxjs.dev/api/operators/filter) You can use `$_` instead of `$_[0]` inside this operator's callback. # 0, 2, 4, 6, ... (every 1.4 seconds) rx_interval(0.7)->pipe( op_filter(sub {$_[0] % 2 == 0}), )->subscribe($observer); # 0, 2, 4, 6, ... (every 1.4 seconds) rx_interval(0.7)->pipe( op_filter(sub {$_ % 2 == 0}), )->subscribe($observer); # 10, 36, 50, complete rx_of(10, 22, 36, 41, 50, 73)->pipe( op_filter(sub ($v, $idx) { $idx % 2 == 0 }), )->subscribe($observer); - op\_finalize [https://rxjs.dev/api/operators/finalize](https://rxjs.dev/api/operators/finalize) _Note:_ Observe, in the second example below, that the order of execution of the finalize callbacks obeys the rxjs v7 order ('f1' first) rather than the rxjs v6 order ('f2' first). # 1, 2, 3, complete, 'hi there' rx_of(1, 2, 3)->pipe( op_finalize(sub { say "hi there" }), )->subscribe($observer); # 0, f1, f2 my $s; $s = rx_interval(1)->pipe( op_finalize(sub { say "f1" }), op_finalize(sub { say "f2" }), )->subscribe(sub { say $_[0]; $s->unsubscribe; }); - op\_first [https://rxjs.dev/api/operators/first](https://rxjs.dev/api/operators/first) # (pause 7 seconds) 6, complete rx_interval(1)->pipe( op_first(sub { $_[0] > 5 }), )->subscribe($observer); # 0, complete rx_interval(0.7)->pipe( op_first(), )->subscribe($observer); - op\_ignore\_elements [https://rxjs.dev/api/operators/ignoreElements](https://rxjs.dev/api/operators/ignoreElements) # (pause 3 seconds) complete rx_interval(1)->pipe( op_take(3), op_ignore_elements(), )->subscribe($observer); # (pause 3 seconds) error: foo rx_concat( rx_interval(1)->pipe(op_take(3)), rx_throw_error('foo'), )->pipe( op_ignore_elements(), )->subscribe($observer); - op\_map [https://rxjs.dev/api/operators/map](https://rxjs.dev/api/operators/map) You can use `$_` instead of `$_[0]` inside this operator's callback. # 10, 11, 12, 13, ... rx_interval(1)->pipe( op_map(sub {$_[0] + 10}), )->subscribe($observer); # 10, 11, 12, 13, ... rx_interval(1)->pipe( op_map(sub {$_ + 10}), )->subscribe($observer); # 10-0, 20-1, 30-2, complete rx_of(10, 20, 30)->pipe( op_map(sub ($v, $idx) { "$v-$idx" }), )->subscribe($observer); - op\_map\_to [https://rxjs.dev/api/operators/mapTo](https://rxjs.dev/api/operators/mapTo) # 123, 123, 123, ... (every 1 second) rx_interval(1)->pipe( op_map_to(123), )->subscribe($observer); - op\_merge\_map [https://rxjs.dev/api/operators/mergeMap](https://rxjs.dev/api/operators/mergeMap) # 11, 21, 31, 12, 22, 32, 13, 23, 33, complete rx_of(10, 20, 30)->pipe( op_merge_map(sub ($x) { return rx_interval(1)->pipe( op_map(sub ($y) { return $x + $y + 1; }), op_take(3), ); }), )->subscribe($observer); - op\_multicast [https://rxjs.dev/api/operators/multicast](https://rxjs.dev/api/operators/multicast) - op\_pairwise [https://rxjs.dev/api/operators/pairwise](https://rxjs.dev/api/operators/pairwise) # [0, 1], [1, 2], [2, 3], ... rx_interval(1)->pipe( op_pairwise, )->subscribe(sub {print Dumper($_[0])}); - op\_pluck [https://rxjs.dev/api/operators/pluck](https://rxjs.dev/api/operators/pluck) # Mary, Paul, undef, undef, undef, complete rx_of( {name => {first => 'Mary'}}, {name => {first => 'Paul'}}, {house => {first => 'Chicago'}}, 15, undef, )->pipe( op_pluck('name', 'first'), )->subscribe($observer); - op\_ref\_count [https://rxjs.dev/api/operators/refCount](https://rxjs.dev/api/operators/refCount) - op\_repeat [https://rxjs.dev/api/operators/repeat](https://rxjs.dev/api/operators/repeat) # 10, 20, 30, 10, 20, 30, 10, 20, 30, complete rx_of(10, 20, 30)->pipe( op_repeat(3), )->subscribe($observer); - op\_retry [https://rxjs.dev/api/operators/retry](https://rxjs.dev/api/operators/retry) # 10, 20, 30, 10, 20, 30, 10, 20, 30, error: foo rx_concat( rx_of(10, 20, 30), rx_throw_error('foo'), )->pipe( op_retry(2), )->subscribe($observer); - op\_sample\_time [https://rxjs.dev/api/operators/sampleTime](https://rxjs.dev/api/operators/sampleTime) Works like rxjs's "sampleTime", except the parameter is in seconds instead of ms. # 0, 2, 3, 5, 6, 8, ... rx_interval(1)->pipe( op_sample_time(1.6), )->subscribe($observer); - op\_scan [https://rxjs.dev/api/operators/scan](https://rxjs.dev/api/operators/scan) # 0, 1, 3, 6, 10, ... rx_interval(1)->pipe( op_scan(sub { my ($acc, $item) = @_; return $acc + $item; }, 0), )->subscribe($observer); - op\_share [https://rxjs.dev/api/operators/share](https://rxjs.dev/api/operators/share) # t0, 0, 0, t1, 1, 1, t2, 2, 2, ... my $o = rx_interval(1)->pipe( op_tap(sub {say 't' . $_[0]}), op_share(), ); $o->subscribe($observer1); $o->subscribe($observer2); - op\_skip [https://rxjs.dev/api/operators/skip](https://rxjs.dev/api/operators/skip) # 40, 50, complete rx_of(10, 20, 30, 40, 50)->pipe( op_skip(3), )->subscribe($observer); - op\_skip\_until [https://rxjs.dev/api/operators/skipUntil](https://rxjs.dev/api/operators/skipUntil) # (pause 4 seconds) 3, 4, 5, ... rx_interval(1)->pipe( op_skip_until( rx_timer(3.5) ), )->subscribe($observer); - op\_start\_with [https://rxjs.dev/api/operators/startWith](https://rxjs.dev/api/operators/startWith) # 100, 200, 0, 1, 2, 3, complete rx_of(0, 1, 2, 3)->pipe( op_start_with(100, 200), )->subscribe($observer); - op\_switch\_map [https://rxjs.dev/api/operators/switchMap](https://rxjs.dev/api/operators/switchMap) # 1, 2, 3, 11, 12, 13, 21, 22, 23, 24, 25, 26, 27, ... my $o = rx_interval(2.5)->pipe( op_take(3) ); $o->pipe( op_switch_map(sub ($x) { return rx_interval(0.7)->pipe( op_map(sub ($y) { $x * 10 + $y + 1 }), ); }), )->subscribe($observer); - op\_take [https://rxjs.dev/api/operators/take](https://rxjs.dev/api/operators/take) # 0, 1, 2, 3, 4, complete rx_interval(1)->pipe( op_take(5), )->subscribe($observer); - op\_take\_until [https://rxjs.dev/api/operators/takeUntil](https://rxjs.dev/api/operators/takeUntil) # 0, 1, 2, 3, 4, complete rx_interval(1)->pipe( op_take_until( rx_timer(5.5) ), )->subscribe($observer); - op\_take\_while [https://rxjs.dev/api/operators/takeWhile](https://rxjs.dev/api/operators/takeWhile) # 0, 1, 2, 3, 4, 5, complete rx_interval(1)->pipe( op_take_while(sub { $_[0] <= 5 }), )->subscribe($observer); # 0, 1, 2, 3, 4, 5, 6, complete rx_interval(1)->pipe( op_take_while(sub { $_[0] <= 5 }, 1), )->subscribe($observer); - op\_tap [https://rxjs.dev/api/operators/tap](https://rxjs.dev/api/operators/tap) # foo0, 0, foo1, 1, foo2, 2, ... rx_interval(1)->pipe( op_tap(sub {say "foo$_[0]"}), )->subscribe($observer); - op\_throttle\_time [https://rxjs.dev/api/operators/throttleTime](https://rxjs.dev/api/operators/throttleTime) Works like rxjs's "throttleTime", except the parameter is in seconds instead of ms. At the moment, this function only accepts `duration` as parameter, not the configuration options that rxjs's throttleTime accepts. # 0, 3, 6, 9, 12, ... rx_interval(1)->pipe( op_throttle_time(2.1), )->subscribe($observer); - op\_with\_latest\_from [https://rxjs.dev/api/operators/withLatestFrom](https://rxjs.dev/api/operators/withLatestFrom) # [0, 0], [1, 1], [2, 3], [3, 4], [4, 6], ... rx_interval(1)->pipe( op_with_latest_from(rx_interval(0.7)), )->subscribe($observer); ## PROMISE FUNCTIONS These functions return a promise or a future, and require the existence of a user-selectable promise library which is automatically loaded in runtime. The functions are borrowed from rxjs 7, and remain experimental until rxjs 7 is finalized. You can optionally set the type of promises returned by these functions with the `RxPerl::AnyEvent->set_promise_class($promise_class)` class method, unless you're using [RxPerl::AnyEvent](https://metacpan.org/pod/RxPerl%3A%3AAnyEvent), in which case it's mandatory. By default the functions return a [Mojo::Promise](https://metacpan.org/pod/Mojo%3A%3APromise) object (when using with [RxPerl::Mojo](https://metacpan.org/pod/RxPerl%3A%3AMojo)), or a [Future](https://metacpan.org/pod/Future) object (when using with [RxPerl::IOAsync](https://metacpan.org/pod/RxPerl%3A%3AIOAsync)). - first\_value\_from Accepts an observable and returns a promise that resolves with the observable's first emitted value as soon as it gets emitted. If no value is emitted before the observable's completion, the promise is rejected. use RxPerl::AnyEvent ':all'; RxPerl::AnyEvent->set_promise_class('Promise::ES6'); my $o = ...; # an observable first_value_from($o)->then( ... ); - last\_value\_from Accepts an observable and returns a promise that resolves with the observable's last emitted value as soon as the observable completes. If no value is emitted before the observable's completion, the promise is rejected. use RxPerl::AnyEvent ':all'; RxPerl::AnyEvent->set_promise_class('Promise::ES6'); my $o = ...; # an observable last_value_from($o)->then( ... ); # OBSERVABLE METHODS - subscribe [http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#instance-method-subscribe](http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#instance-method-subscribe) $o->subscribe( sub {say "next: $_[0]"}, sub {say "error: $_[0]"}, sub {say "complete"}, ); $o->subscribe( undef, sub {say "error: $_[0]"}, ); $o->subscribe({ next => sub {say "next: $_[0]"}, complete => sub {say "complete"}, }); - pipe [http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#instance-method-pipe](http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#instance-method-pipe) # 2, 6, complete rx_interval(1)->pipe( op_take(5), op_filter(sub {$_[0] % 2 == 1}), op_map(sub {2 * $_[0]}), )->subscribe(...) # CONNECTABLE OBSERVABLE METHODS Connectable observables are a subclass of observables, which (like Subjects) are multicasting and can start emitting even before anyone subscribes to them, by invoking a method. They are usually created and returned by the ["op\_multicast"](#op_multicast) pipeable operator. - connect Makes the connectable observable start emitting. $o->connect; # SUBJECT METHODS Subjects multicast, and apart from being observables themselves (with their own subscribers), also have [next, error and complete](#next-error-complete) methods of their own, so can be used as the observer argument to another observable's subscribe method. That observable's events will then be "forwarded" to the subject's own subscribers, as if next/error/complete had been called on the subject directly. - next, error, complete Calling these methods manually will cause the subject's subscribers to receive the corresponding events. Typically subjects don't emit anything on their own (as opposed to ["rx\_interval"](#rx_interval) et al), although it is possible to create a subclass of Subject that behaves differently. An example is a queueing subject that accumulates events from the observable it has been subscribed to, then emits all of them at once to the first subscriber that subscribes to it. # NAMING CONVENTIONS To prevent naming collisions with Perl’s built-in functions (or the user’s own), as rxjs’s operators are often small english words (such as `map`), the names of this module’s operators start with `rx_` or `op_`. Functions that in the JS world would be imported from 'rxjs' have their corresponding RxPerl names prepended with `rx_`, whereas functions imported from 'rxjs/operators' (namely pipeable opreators) start with `op_` in RxPerl. import {Observable, Subject, timer, interval} from 'rxjs'; import {map, filter, delay} from 'rxjs/operators'; becomes: use RxPerl::IOAsync qw/ rx_observable rx_subject rx_timer rx_interval op_map op_filter op_delay /; # CAVEATS Since the [rxjs implementation](https://rxjs.dev/api/) differs from the [ReactiveX API](http://reactivex.io/documentation/operators.html) at a few points (as do most of the [Rx\* libraries](http://reactivex.io/languages.html)), RxPerl chose to behave like rxjs rather than ReactiveX to cater for web developers already familiar with rxjs. # LEARNING RESOURCES - [RxJS Top Ten - Code This, Not That](https://www.youtube.com/watch?v=ewcoEYS85Co) - [Ultimate RxJS courses](https://ultimatecourses.com/courses/rxjs) _(paid)_ - [egghead RxJS courses](https://egghead.io/browse/libraries/rxjs) _(paid)_ - [Rx Marbles](https://rxmarbles.com/) # SEE ALSO - [Ryu](https://metacpan.org/pod/Ryu) # NOTIFICATIONS FOR NEW RELEASES You can start receiving emails for new releases of this module, at [https://perlmodules.net](https://perlmodules.net). # COMMUNITY CODE OF CONDUCT The Community Code of Conduct can be found [here](https://metacpan.org/pod/RxPerl%3A%3ACodeOfConduct). # LICENSE Copyright (C) 2020 Karelcom OÜ. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. # AUTHOR Alexander Karelas <karjala@cpan.org>