define( ‘WP_DEBUG’, true );
define( ‘WP_DEBUG_DISPLAY’, false );
define( ‘WP_DEBUG_LOG’, true );

if ( ! function_exists(‘write_log’)) {
function write_log ( $log ) {
if ( is_array( $log ) || is_object( $log ) ) {
error_log( print_r( $log, true ) );
} else {
error_log( $log );
}
}
}

https://www.elegantthemes.com/blog/tips-tricks/using-the-wordpress-debug-log