Show specific dates that are in the Database in Bootstrap datapicker

Question

I need the datapicker to load specific dates dynamically, which are saved in the database, I was able to get it to load manually, but there are several dates and may vary as the user saves in the database.

I am using the following code, which displays manually selected dates with a specific color:

<script>
var active_dates = ["2-9-2019","22-9-2019"];

$('.datepicker').datepicker({
    autoclose: true,
    format: "dd-mm-yyyy",
    beforeShowDay: function(date){
     var d = date;
     var curr_date = d.getDate();
     var curr_month = d.getMonth() + 1;
     var curr_year = d.getFullYear();
     var formattedDate = curr_date + "-" + curr_month + "-" + curr_year

       if ($.inArray(formattedDate, active_dates) != -1){
           return {
              classes: 'activeClass'
           };
       }
      return;
  }
});
$(".datepicker").attr("autocomplete", "off");
</script>

CSS:

.activeClass{
color: #ecf0f1;
background: #2980b9; 
}     

Upshot:

After some researches and studies I saw that it is possible to pass data from a php variable to javascript. Exemplifying:

<?php
 $color = "Red";
?>

In javascript:

var color = "<?php echo $color; ?>";

I’m trying this way, but without success!:

<?php 
  $diasValidos = $this->db->get_where('school_days')->result_array();
?>

In the Datapicker:

<script>
var active_dates = <?php $diasValidos ?>;

$('.datepicker').datepicker({
    autoclose: true,
    format: "dd-mm-yyyy",
    beforeShowDay: function(date){
     var d = date;
     var curr_date = d.getDate();
     var curr_month = d.getMonth() + 1;
     var curr_year = d.getFullYear();
     var formattedDate = curr_date + "-" + curr_month + "-" + curr_year

       if ($.inArray(formattedDate, active_dates) != -1){
           return {
              classes: 'activeClass'
           };
       }
      return;
  }
});
$(".datepicker").attr("autocomplete", "off");
</script>

Table print in database:

Answer 1

There are two possible problems, probably the return of

$diasValidos = $this->db->get_where('school_days')->result_array()

is not coming with an array of dates, and if you are searching for the dates in the database, and the column is like datetime, the return date will be Y-m-d, then the way you are forming the date to compare is wrong.

As requested, it is necessary to know the return for $diasValidos, in order to help.

EDITED:

Considering the return array(4) { ["id"]=> string(1) "5" ["day"]=> string(2) "21" ["month"]=> string(1) "1" ["year"]=> string(4) "2019" },

Just refactor your array to join day, month and year, a shape would be:

$diasValidos = array_map(function($diaValido) {
    return $diaValido['day'] + "-" + $diaValido['month'] + "-" + $diaValido['year'];
}, $diasValidos);