YearMonthDate.php

<?php

namespace Drupal\views\Plugin\views\argument;

use Drupal\views\Attribute\ViewsArgument;

/**
 * Argument handler for a year plus month (CCYYMM)
 */
class YearMonthDate extends Date {
    
    /**
     * {@inheritdoc}
     */
    protected $format = 'F Y';
    
    /**
     * {@inheritdoc}
     */
    protected $argFormat = 'Ym';
    
    /**
     * {@inheritdoc}
     */
    public function summaryName($data) {
        $created = $data->{$this->name_alias};
        return $this->dateFormatter
            ->format(strtotime($created . "15" . " 00:00:00 UTC"), 'custom', $this->format, 'UTC');
    }
    
    /**
     * {@inheritdoc}
     */
    public function title() {
        return $this->dateFormatter
            ->format(strtotime($this->argument . "15" . " 00:00:00 UTC"), 'custom', $this->format, 'UTC');
    }

}