根据基于数据库值的可用天数更新datepicker

Question

I am currently trying to disable certain days on the jquery datepicker based on values which are taken from a mysql database and stored in a php array. I am having trouble converting the php array into jquery and then reading the values to disable the days which have not been selected to be available for the user. Could anyone walk me through what I have to do to create this functionality. I am a bit lost in the process after encoding the php array into json

 $daysavailquery = "SELECT Monday, Tuesday, Wednesday, Thursday, Friday, 
 Saturday, Sunday FROM miiLearning_tutorAvail WHERE id = 
 $id";

$daysavailresult = mysqli_query($conn, $daysavailquery);

$daysavailarray = mysqli_fetch_array($daysavailresult);

//Convert days avail to json
$DaysAvailJSON = json_encode($daysavailarray);
echo $DaysAvailJSON;

<script>
        $( function() {


            $( "#datepicker" ).datepicker({
                dateFormat: "yy-mm-dd"
                var daysAvailArray = <?php echo json_encode($daysavailarray) ?>
                beforeShowDay: function(date) {

                var day = date.getDay();
                console.log(day);

                if (day == 0 && daysAvailArray[0]==1)
                  return [true];
                if (day == 1 && daysAvailArray[0]==1)
                  return [true];
                if (day == 2 && daysAvailArray[0]==1)
                  return [true];
                if (day == 3 && daysAvailArray[0]==1)
                  return [true];
                if (day == 4 && daysAvailArray[0]==1)
                  return [true];
                if (day == 5 && daysAvailArray[0]==1)
                  return [true];
                if (day == 6 && daysAvailArray[0]==1)
                  return [true];

                return [false];
              }
            });
        } );
    </script>

<div class="form-group">
     <label for="datepicker">Pick a date</label>
     <input type="text" date-date- format="yy-mm-dd" name="datepicker" 
id="datepicker" class="form-control" required>
</div>

Answer 1

I will assume that the table contains true or false value for each day.

$daysavailarray = mysqli_fetch_array($daysavailresult);
// should be have associate array
//[ 'monday' => '1', 'Sunday' => '0']
// we don't need the day name so we will use MYSQLI_NUM to have it as numerical index [ 0 => '1' , 1 => '0' ]
$daysavailarray = mysqli_fetch_array($daysavailresult, MYSQLI_NUM);

Now want to convert the php array to javascript array json_encode will do the job

var daysAvailArray = <?php echo json_encode($daysavailarray) ?>;

Because we have the day as index it will be easier to see if it false or not

var day = date.getDay();
console.log(day);
return daysAvailArray[day-1] ? [true] : [false];

The complete javascript code

<script>
    $( function() {
        var daysAvailArray = <?php echo json_encode($daysavailarray) ?>;
        $( "#datepicker" ).datepicker({
            dateFormat: "yy-mm-dd",
            beforeShowDay: function(date) {
                var day = date.getDay();
                return (daysAvailArray[day-1] == '1') ? [true] : [false];                           
            }
        });
    } );
</script>