Return from json_encode fails

I have the jssor slider installed and working. I am trying to add the ability to change the slide type from an external file using php. In my unedited jssor code, if I enter the following as the slide types, they work as expected:

    {$Duration:800,$Opacity:2},
    {$Duration:1000,y:1,$Easing:$Jease$.$InBounce,$Opacity:2}

When I try to load from a function, as illustrated in the code below, the output of the console command is

    0: "{$Duration:800,$Opacity:2},"
    1: "{$Duration:1000,y:1,$Easing:$Jease$.$InBounce,$Opacity:2}"

If I strip off the quotes and place those in the _SlideshowTransitions function they work. So is it the quotes that are causing a problem? If so, how can I remove those? Or is it that the jssor function won't work with a variable? Or something else?

    function GetTransitions() {
        $xsisitons = array();
        $xsisitons[] = '{$Duration:800,$Opacity:2},';
        $xsisitons[] = '{$Duration:1000,y:1,$Easing:$Jease$.$InBounce,$Opacity:2}';
        return json_encode($xsisitons);
    }
    $jsondata = GetTransitions(); 

    <script>
    var xsitions = <?php echo $jsondata; ?>;
    console.dir(xsitions);

    var _SlideshowTransitions = [
      xsitions
    ];
    </script>

Solution

Simply create the JS directly:

<?php
    function GetTransitions() {
        return $rawJS = '[
            {
                $Duration: 800,
                $Opacity: 2
            },
            {
                $Duration: 1000,
                y: 1,
                $Easing: $Jease$.$InBounce,
                $Opacity: 2
            }
        ]';
    }
    $options = GetTransitions(); 
?>
    <script>
    var xsitions = <?php echo $options; ?>;
    console.dir(xsitions);

    var _SlideshowTransitions = xsitions;
    </script>

This is the line that prevents you from using json_encode:

$Easing: $Jease$.$InBounce,

json_encode would treat $Jease$.$InBounce as a string rather than JS code, preventing it from functioning as expected.

That makes GetTransitions extremely dangerous, which is hinted at by the new variable name rawJS. Make sure you pay attention to what that function outputs.

You could safely make $Duration, $Opacity, and y dynamic in the PHP by casting input variables to int when building the $rawJS string, or by escaping the dynamic values (but not the whole string) with json_encode:

function GetTransitions($duration_1, $duration_2, $opacity, $y) {
    return $rawJS = '[
        {
            $Duration: ' . (int)$duration_1 . ',
            $Opacity: ' . (int)$opacity . '
        },
        {
            $Duration: ' . (int)$duration_2 . ',
            y: ' . (int)$y . ',
            $Easing: $Jease$.$InBounce,
            $Opacity: ' . (int)$opacity . '
        }
    ]';
}