How to add filename and file extension to window.open method that exports a JSON array to a CSV string then to a file in javascript?

Question

I have the following code, which was found on the following question: https://stackoverflow.com/a/4130939/1055971

function DownloadJSON2CSV(objArray)
{
    var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;

    var str = '';

    for (var i = 0; i < array.length; i++) {
        var line = '';

        for (var index in array[i]) {
            line += array[i][index] + ',';
        }

        line.slice(0,line.Length-1); 

        str += line + '\r\n';
    }

    window.open( "data:text/csv;charset=utf-8," + escape(str))

}

This code works very well. It downloads the file and saves it, but the issue is there is not a way to add a custom title to the file, and also, the file saves with no extension. For example, when the save function is called, the file name is 'download' by default with no file extension. When i add an extension through the windows file system (like .csv) and open the file again, all data is perfectly preserved.
I am hoping to figure out a way to preset the file name and file type before the download takes place. Any ideas?

Answer 1

create invisible link element( anchor tag) and initialize download property of a element with desired file name and append in new created window and open and call programmatically click event on created a element.

$(document).ready(function(){
    $('button').click(function(){
        var data = $('#txt').val();
        if(data == '')
            return;
        
        JSONToCSVConvertor(data, "Sample Report", true);
    });
});

function JSONToCSVConvertor(JSONData, ReportTitle, ShowLabel) {
    //If JSONData is not an object then JSON.parse will parse the JSON string in an Object
    var arrData = typeof JSONData != 'object' ? JSON.parse(JSONData) : JSONData;
    
    var CSV = '';    
    //Set Report title in first row or line
    
    CSV += ReportTitle + '\r\n\n';

    //This condition will generate the Label/Header
    if (ShowLabel) {
        var row = "";
        
        //This loop will extract the label from 1st index of on array
        for (var index in arrData[0]) {
            
            //Now convert each value to string and comma-seprated
            row += index + ',';
        }

        row = row.slice(0, -1);
        
        //append Label row with line break
        CSV += row + '\r\n';
    }
    
    //1st loop is to extract each row
    for (var i = 0; i < arrData.length; i++) {
        var row = "";
        
        //2nd loop will extract each column and convert it in string comma-seprated
        for (var index in arrData[i]) {
            row += '"' + arrData[i][index] + '",';
        }

        row.slice(0, row.length - 1);
        
        //add a line break after each row
        CSV += row + '\r\n';
    }

    if (CSV == '') {        
        alert("Invalid data");
        return;
    }   
    
    //Generate a file name
    var fileName = "MyReport_";
    //this will remove the blank-spaces from the title and replace it with an underscore
    fileName += ReportTitle.replace(/ /g,"_");   
    
    //Initialize file format you want csv or xls
    var uri = 'data:text/csv;charset=utf-8,' + escape(CSV);
    
    // Now the little tricky part.
    // you can use either>> window.open(uri);
    // but this will not work in some browsers
    // or you will not get the correct file extension    
    
    //this trick will generate a temp <a /> tag
    var link = document.createElement("a");    
    link.href = uri;
    
    //set the visibility hidden so it will not effect on your web-layout
    link.style = "visibility:hidden";
    link.download = fileName + ".csv";
    
    //this part will append the anchor tag and remove it after automatic click
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
}

.txtarea{
    max-width:100%;
    min-height:200px;    
    display:block;
    width:100%;
}

.mydiv{
    padding:10px;
}

.gen_btn{
    padding:5px;
    background-color:#743ED9;
    color:white;
    font-family:arial;
    font-size:13px;
    border:2px solid black;
}

.gen_btn:hover{
    background-color:#9a64ff;
}

<div class='mydiv'>    
    <textarea id="txt" class='txtarea'>[{"Vehicle":"BMW","Date":"30, Jul 2013 09:24 AM","Location":"Hauz Khas, Enclave, New Delhi, Delhi, India","Speed":42},{"Vehicle":"Honda CBR","Date":"30, Jul 2013 12:00 AM","Location":"Military Road,  West Bengal 734013,  India","Speed":0},{"Vehicle":"Supra","Date":"30, Jul 2013 07:53 AM","Location":"Sec-45, St. Angel's School, Gurgaon, Haryana, India","Speed":58},{"Vehicle":"Land Cruiser","Date":"30, Jul 2013 09:35 AM","Location":"DLF Phase I, Marble Market, Gurgaon, Haryana, India","Speed":83},{"Vehicle":"Suzuki Swift","Date":"30, Jul 2013 12:02 AM","Location":"Behind Central Bank RO, Ram Krishna Rd by-lane, Siliguri, West Bengal, India","Speed":0},{"Vehicle":"Honda Civic","Date":"30, Jul 2013 12:00 AM","Location":"Behind Central Bank RO, Ram Krishna Rd by-lane, Siliguri, West Bengal, India","Speed":0},{"Vehicle":"Honda Accord","Date":"30, Jul 2013 11:05 AM","Location":"DLF Phase IV, Super Mart 1, Gurgaon, Haryana, India","Speed":71}]</textarea>
    <button class='gen_btn'>Generate File</button>
</div>

Answer 2

//taken from https://stackoverflow.com/questions/283956/is-there-any-way-to-specify-a-suggested-filename-when-using-data-uri#15832569
function downloadWithName(uri, name) {
    function eventFire(el, etype){
        if (el.fireEvent) {
            (el.fireEvent('on' + etype));
        } else {
            var evObj = document.createEvent('Events');
            evObj.initEvent(etype, true, false);
            el.dispatchEvent(evObj);
        }
    }

    var link = document.createElement("a");
    link.download = name;
    link.href = uri;
    eventFire(link, "click");
}

downloadWithName("data:text/csv;charset=utf-8," + escape(str), "file.csv"); //didnt work when I tested in ff25

There appears to not be a good way to guarantee the behaviour cross browser