print to html console from php code example

Example 1: php print to console

<script>
    console.log(<?= json_encode($foo); ?>);
</script>

Example 2: php console print

$a = array(
 null => 'a',
 true => 'b',
 false => 'c',
 0 => 'd',
 1 => 'e',
 '' => 'f'
);

echo count($a), "\n";