TanggalCicilan.php

<?php

class ClassName
{
    private function date_range($first, $last, $step = '+1 day', $output_format = 'Y-m-d' )
    {
        $dates = array();
        $current = strtotime($first);
        $last = strtotime($last);
    
        while( $current <= $last ) {
    
            $dates[] = date($output_format, $current);
            $current = strtotime($step, $current);
        }
    
        return $dates;
    }

    public function store()
    {
        $mulai = date("Y-m-d");
        $akhir = date("Y-m-d", strtotime($mulai." +12 week"));
        $data = $this->date_range($mulai, $akhir, "+7 day");
        
        $data_libur = array('2020-08-17', '2020-08-21');
        $tanggal_cicilan = array();
        
        foreach ($data as $tanggal) {
            if (!in_array($tanggal, $data_libur)){
                $tanggal_cicilan[] = $tanggal;
            }
        }
        
        var_export($tanggal_cicilan);
    }
}