Convert php object to javascript object?

Question

PHP

Tell me how to do it. The problem is simple but not solved.
There is a php object.

<?
$vi = array(
'a'=>1,
'b'=>2
);
?>

You need to get this object in javascript
in the following form, respectively

var vi = {
a:1,
b:2
};

I complicate the task a little by the fact that all this scale is in the heredoc

<?
echo<<<heredoc
<script>
var vi = {
a:1,
b:2
};
</script>
heredoc;

Answer 1

php.net/manual/en/function.json-encode.php

Answer 2

<?php 
$vi = array(
'a'=>1,
'b'=>2
);
foreach ($vi as $key => $value) {
    $result[] = $key . ':' . $value;
}
$result = implode(",\n", $result);
?>
<script>
var vi = {
<?=$result?>

}
</script>