Will it be PHP safe to output directory contents and read them using JQuery?

My question is about PHP security for this specific operation:

I want to use javascript to pull all json files from a specific directory on my web server. I did this: I am pulling out all the correct filenames with this PHP script ("get-data.php"):

<?php
echo json_encode(glob('*.json'));
?>

      

        
        
        
      

    

Then I move this array to javascript with

var oReq = new XMLHttpRequest();
oReq.onload = function() {
    fileNames = JSON.parse(this.responseText);
};
oReq.open("get", "get-data.php", true);
oReq.send();

      

        
        
        
      

    

Then I use the following to read the files into an array:

function getMapInfo(fileName){
    $.get(fileName, function(result) {
        var map = JSON.parse(result);
        mapData.push(map);
    });
 }

      

        
        
        
      

    

I got some of this code from here: How to pass variables and data from PHP to JavaScript? and i read the xss a bit here and here and i understand that "untrusted data" is the data that the user enters, which will then be executed in the script? I believe my above solution contains no unsafe data as it only pulls files that are already on my server, right?

Overall, my question is, is this a safe way to allow my code to fetch multiple unknown files from my server? In the end, I want to use to "save" the map data to a server, which will then be read by the above script for others to view.

Many thanks,

Jordan