Convert Json to CSV format & popout form

Json2CSV.js

//Convert to csv
downloadCSVFromJson = (filename, arrayOfJson) => {
   // convert JSON to CSV
   const replacer = (key, value) => value === null ? '' : value // specify how you want to handle null values here
   const header = Object.keys(arrayOfJson[0])
   let csv = arrayOfJson.map(row => header.map(fieldName => 
   JSON.stringify(row[fieldName], replacer)).join(','))
   csv.unshift(header.join(','))
   csv = csv.join('\r\n')

   // Create link and download
   var link = document.createElement('a');
   link.setAttribute('href', 'data:text/csv;charset=utf-8,%EF%BB%BF' + encodeURIComponent(csv));
   link.setAttribute('download', filename);
   link.style.visibility = 'hidden';
   document.body.appendChild(link);
   link.click();
   document.body.removeChild(link);
 };

PopOutForm.js

//Form hide
// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
    var forms = document.getElementsByClassName('modal');
    var Currform;
    for (let form of forms) {
        if(form.style.display == 'block')
           Currform = form;
    }
    if(event.target == Currform){
        Currform.style.display = "none";
    }
}