How can i iterate over the row and print the objects value in excel in node js?

You can loop through your data and make sure that you skip the header row that you created.

Excel rows start at row 1 and your array is index 0 so you need to make sure that you always start at either 1 when writing to Excel or in your case start at row 2 since you created a header row (that's why you'll see ws.cell(i + 2, 1).string(data[i].FirstName);).

Here is a sample express app:

Dependencies:

npm install express
npm install excel4node

Code:

const express = require('express');
const xl = require('excel4node');

const app = express();

app.get('/', (req, res) => {
  try {
    const data = [
      {   "FirstName": "John", 
          "LastName": "Parker", 
          "Age": "23", 
          "Cat": "23g",
          "SOP": "Active"
      },
      {   "FirstName": "Rose", 
          "LastName": "Jackson", 
          "Age": "44", 
          "Cat": "44g",
          "SOP": "InActive"
      }
    ];

    const wb = new xl.Workbook();

    // Add Worksheets to the workbook
    const ws = wb.addWorksheet('Report');

    ws.cell(1, 1).string('FirstName');
    ws.cell(1, 2).string('LastName');
    ws.cell(1, 3).string('Age');
    ws.cell(1, 4).string('Cat');
    ws.cell(1, 5).string('SOP');

    for (let i = 0; i < data.length; i += 1) {
      ws.cell(i + 2, 1).string(data[i].FirstName);
      ws.cell(i + 2, 2).string(data[i].LastName);
      ws.cell(i + 2, 3).string(data[i].Age);
      ws.cell(i + 2, 4).string(data[i].Cat);
      ws.cell(i + 2, 5).string(data[i].SOP);
    }

    const fileName = `Report_${Date.now().toString()}.xlsx`;

    res.setHeader('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
    res.setHeader("Content-Disposition", "attachment; filename=" + fileName);
    wb.write(fileName, res);

  } catch (err) {
      console.error(res, err);
  }
});

app.listen(3000, () => console.log('Example app listening on port 3000!'))