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Evo-0.0192
⭐ Starred 4 / Evo::Promises

NAME

Evo::Promises

VERSION

version 0.0192

FUNCTIONS

promise

promise(
  sub($resolve, $reject) {
    loop_timer 1 => sub { $resolve->('HELLO') };
  }
)->then(sub($v) { say "Fulfilled: $v"; });

Return ES6 syntax promise. The first argument should be a function. Resolve and reject handlers(functions) will be passed to it

Only the first invocation of either $resolve or $reject matters. The second one will be ignored.

deferred

Create a promise and attach it to the deferred object. Deferred object is a handler for the promise.

my $d = deferred();
loop_timer 1 => sub { $d->resolve('HELLO') };
$d->promise->then(sub($v) { say "Fulfilled: $v"; });

promises_resolve

my $p = promises_resolve('hello');

Generate a resolved promise with a given value. If value is a thenable object or another promise, the resulting promise will follow it. Otherwise it will be fulfilled with that value

promises_reject

my $p = promises_reject('hello');

Generate a rejected promise with a reason. If the reason is a promise, resulting promise will NOT follow it.

promises_all

Creates a promise that will be resolved only when all promises are resolved. The result will be an array containing resolved value with the same order, as passed to this function. If one of the collected promises become rejected, that promise will be rejected to with that reason.

my ($d1, $d2) = (deferred, deferred);
loop_timer 1,   sub { $d1->resolve('first') };
loop_timer 0.1, sub { $d2->resolve('second') };

promises_all($d1->promise, $d2->promise)->then(sub($v) { say join ';', $v->@* });

Will print first;second

promises_race

Return a promise that will be resolved or rejected with the value/reason of the first resolved/rejected promise

promises_race($d1->promise, $d1->promise)->then(sub($v) { say $v });

loop_timer 1 => sub { $d1->resolve('1') };
loop_timer 2 => sub { $d2->resolve('2') };

Will print 2

fin

Chain promise with a handler, that gets called with no argument when the parent promise is settled(fulfilled or rejected). When that handler returns a result, the next promise gets postponed. Value are ignored. If that handler causes an exception or returns rejected promise (or promise that will eventually gets rejected), the chain would be rejected.

A shorter. Causes no effect on the chain unless rejection happens

promises_resolve('VAL')->fin(sub() {'IGNORED'})->then(sub($v) { say $v});

Usefull for closing connections etc. The idea described here: https://github.com/kriskowal/q#propagation

SEE ALSO

More info about promises, race, all etc.: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Promise

AUTHOR

alexbyk.com

COPYRIGHT AND LICENSE

This software is copyright (c) 2016 by alexbyk.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.