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gquemener/in-memory-projection.php

Created July 9, 2018 19:53
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  1. gquemener created this gist Jul 9, 2018.
    40 changes: 40 additions & 0 deletions in-memory-projection.php
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,40 @@
    <?php

    require __DIR__.'/vendor/autoload.php';

    use Rx\Observable;
    use Rx\Observer\CallbackObserver;

    $events = Observable::fromArray([
    ['name' => 'account_was_created', 'payload' => ['id' => 1, 'owner' => 'Gildas Quéméner']],
    ['name' => 'deposit_was_performed', 'payload' => ['id' => 1, 'amount' => 100]],
    ['name' => 'withdrawal_was_performed', 'payload' => ['id' => 1, 'amount' => 100]],
    ['name' => 'deposit_was_performed', 'payload' => ['id' => 1, 'amount' => 40]],
    ]);

    $events
    ->scan(function(array $state, array $event): array {
    switch ($event['name']) {
    case 'account_was_created':
    return array_merge($state, $event['payload'], ['amount' => 0]);

    case 'withdrawal_was_performed':
    return array_merge($state, ['amount' => $state['amount'] - $event['payload']['amount']]);

    case 'deposit_was_performed':
    return array_merge($state, ['amount' => $state['amount'] + $event['payload']['amount']]);
    }

    return $state;
    }, [])
    ->subscribe(new CallbackObserver(
    function(array $state) {
    echo json_encode($state) . PHP_EOL;
    },
    function() {
    printf('ERROR' . PHP_EOL);
    },
    function() {
    printf('COMPLETED' . PHP_EOL);
    }
    ));