Do comparision after updates hooks of acf-fields?

Question

I have this code:

public function init() {
    add_filter('acf/update_value/name=bookitall_fromdate', 
    array($this, 'check_bookingdates' ), 10, 3);

    add_filter('acf/update_value/name=bookitall_todate', 
    array($this, 'check_bookingdates' ), 10, 3);
}

public function check_bookingdates($new_value, $post_id, $field) {

    $post_type = get_post_type( $post_id );           
    if ( $post_type != 'bookitall_bookings' ) 
    {
        return;
    }        
    $old_value = get_post_meta($post_id, $field['name'], true);
    if ( $old_value == $new_value ) { //No change
        return $new_value; 
    }      

    ...code to check (comparision) fromdate and to date

}

I want to compare dates and add dates or remove dates from another tables based on from- and to-date.

The issue is that from- date and to-date can be totally different depending in which order the hooks acf/update_value/name=bookitall_fromdate and acf/update_value/name=bookitall_todate occurs. I want to do the comparision when both datefields (bookitall_fromdate and bookitall_todate) has been updated.

How do I achieve that?

This doesn't have to be with acf-fields. The same question applies when using relevant update_meta_key in a filter.

Answer 1

ACF launches these hooks on the hook save_post then you can compare values just before like that :

add_action("save_post", function ($post_ID, \WP_Post $post, bool $update) {

    // read old values with get_post_meta($post_id, "bookitall_fromdate", TRUE) ...

    // read new values in $_POST


    // do action if the 2 dates are changed



}, 6, 3); // priority 6 for launching before ACF saving with priority 10