its for frontend developers help to develop unknown file length when develop frontend

fakefilecreator.js

 function chunkArray(myArray, chunk_size){
    var results = [];
    
    while (myArray.length) {
        results.push(myArray.splice(0, chunk_size));
    }
    
    return results;
}
        function filecreator (filetypes,namelength){
          /*https://stackoverflow.com/questions/1497481/javascript-password-generator */
          var filetype=filetypes[Math.floor(Math.random() * 2)];
          var  charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",
               retVal = "";
           for (var i = 0, n = charset.length; i < namelength; ++i) {
               retVal += charset.charAt(Math.floor(Math.random() * n));
           }
          var file=retVal+filetype;
          return file
       
           }
           function  filemanager(filetypes,n,namelength ){
             var returnvalue=''
             var files =[];
       
            for (let index = 0; index < n; index++) {
               files[index]=filecreator(filetypes,namelength)
               returnvalue += (files[index]+',')
            }
           console.log(returnvalue);
            var result = chunkArray(files,51);
            console.log(result);

            var paginator = document.getElementById("pagi");
             var pagin='';
             for (var l= 0; l < 4;l++) {
              pagin += '<ul class=col-md-3>';
                for (var k= 0; k < 15; k++) {
                 pagin += '<li><a href="#">' +result[length][k]+ '</a></li>';
                 }
                 pagin += '</ul>';
             }
                 paginator.innerHTML = pagin
               
         
           }
           var filetypes=[".audio",".flac"]
           filemanager(filetypes,60,1 )    
       
              </script>