JAVASCRIPT

create csv file javascript

 $("#download_1").click(function() {
var json_pre = '[{"Id":1,"UserName":"Sam Smith"},{"Id":2,"UserName":"Fred Frankly"},{"Id":1,"UserName":"Zachary Zupers"}]';
var json = $.parseJSON(json_pre);

var csv = JSON2CSV(json);
var downloadLink = document.createElement("a");
var blob = new Blob(["ufeff", csv]);
var url = URL.createObjectURL(blob);
downloadLink.href = url;
downloadLink.download = "data.csv";

document.body.appendChild(downloadLink);
downloadLink.click();
document.body.removeChild(downloadLink);
});

create csv file javascript

function JSON2CSV(objArray) {
    var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;
    var str = '';
    var line = '';

    if ($("#labels").is(':checked')) {
        var head = array[0];
        if ($("#quote").is(':checked')) {
            for (var index in array[0]) {
                var value = index + "";
                line += '"' + value.replace(/"/g, '""') + '",';
            }
        } else {
            for (var index in array[0]) {
                line += index + ',';
            }
        }

        line = line.slice(0, -1);
        str += line + '
';
    }

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

        if ($("#quote").is(':checked')) {
            for (var index in array[i]) {
                var value = array[i][index] + "";
                line += '"' + value.replace(/"/g, '""') + '",';
            }
        } else {
            for (var index in array[i]) {
                line += array[i][index] + ',';
            }
        }

        line = line.slice(0, -1);
        str += line + '
';
    }
    return str;
}

export csv single javascript

//EXPORT SINGLE COLUMN CSV JAVASCRIPT
function downloadCSV(csv, filename) {
var csvFile;
var downloadLink;
csvFile = new Blob([csv], {type: "text/csv"});
downloadLink = document.createElement("a");
downloadLink.download = filename;
downloadLink.href = window.URL.createObjectURL(csvFile);
downloadLink.style.display = "none";
document.body.appendChild(downloadLink);
downloadLink.click();
}
//export
function exportss(filename) {
var csv = [];
var rows = document.querySelectorAll("table tr");
let aa = Array.from(rows).map((x,y)=> {
var row = [], cols = rows[y].querySelectorAll("td, th"); 
    Array.from(cols).forEach((a,b)=>{
        row.push(cols[b].innerText);
    })
    csv.push(row.join(","))
    console.log(csv)   
    return x
    })
downloadCSV(csv.join("
"), filename);
}

combine csv files javascript

const file1 = 'one.csv';
const file2 = 'two.csv';
const stream = fs.createReadStream(file1);
const stream2 = fs.createReadStream(file2);
const fileData1 = [];
const fileData2 = [];

const file1Promise = new Promise((resolve) => {
  csv
      .parseFile(file1, {headers: true})
      .on('data', function(data) {
        fileData1.push(data);
      })
      .on('end', function() {
        console.log('done');
        resolve();
      });
});

const file2Promise = new Promise((resolve) => {
  csv
      .parseFile(file2, {headers: true})
      .on('data', function(data) {
        fileData2.push(data);
      })
      .on('end', function() {
        console.log('done');
        resolve();
      });
});

Promise.all([
  file1Promise,
  file2Promise,
])
    .then(() => {
      const fileData3 = fileData1.concat(fileData2);
      console.log(fileData3);

      const csvStream = csv.format({headers: true});
      const writableStream = fs.createWriteStream('outputfile.csv');

      writableStream.on('finish', function() {
        console.log('DONE!');
      });

      csvStream.pipe(writableStream);
      fileData3.forEach((data) => {
        csvStream.write(data);
      });
      csvStream.end();
    });

combine csv files javascript

var file1 = appRoot + 'csvFilesdetails1.csv';
var file2 = appRoot + 'csvFilesidetails2.csv';
var stream = fs.createReadStream(file1);
var stream2 = fs.createReadStream(file2);
var fileData1 = [],
    fileData2 = [],
    i = 0;

csv.fromStream(stream).on("data", function(data) {
    fileData1.push(data);
}).on("end", function() {
    csv.fromStream(stream2).on("data", function(data) {
        if (i != 0) {
            fileData2.push(data);
        }
        i++;
    }).on("end", function() {
        console.log("done");
        var fileData3 = fileData1.concat(fileData2);
        csv.writeToPath("outputfile.csv", fileData3).on("finish", function() {
            res.send('Done merge');
        });
    });
});