Excel file not downloading by using excel4node in MeanStack

Hi I want to download the excel file by clicking the Export button.

I am using this reference link to create the excel file https://www.npmjs.com/package/excel4node

Html page

<button ng-click="exportData()" class="btn btn-sm btn-primary btn-create">Export</button>

Controller.js

 $scope.exportData = function () {
         $http.get('/Getexcel').then(function (response) {
         });
     };

Server.js

var xl = require('excel4node');
const tempfile = require('tempfile');

// Create a new instance of a Workbook class 
var wb = new xl.Workbook();

// Add Worksheets to the workbook 
var ws = wb.addWorksheet('MaterialFlowSheet');


// Create a reusable style 
var style = wb.createStyle({
    font: {
        color: '#FF0800',
        size: 12
    },
    numberFormat: '$#,##0.00; ($#,##0.00); -'
});


app.get('/Getexcel', function (req, res) {
    ws.cell(1, 1).string('BatchId').style(style);
    ws.cell(1, 2).string('Source').style(style);
    ws.column(2).setWidth(50);
    ws.row(1).setHeight(20);
    ws.cell(1, 3).string('Destination').style(style);
    ws.column(3).setWidth(50);
    ws.row(1).setHeight(20);
    ws.cell(1, 4).string('DistanceBetweenTwoBuilding').style(style);
    ws.column(4).setWidth(25);
    ws.row(1).setHeight(20);
    ws.cell(1, 5).string('SKU').style(style);
    ws.cell(1, 6).string('UOM').style(style);
    ws.cell(1, 7).string('QtyToBeDelivered').style(style);
    ws.column(7).setWidth(20);
    ws.row(1).setHeight(20);
    ws.cell(1, 8).string('CartType').style(style);

    ws.addDataValidation({
        type: 'list',
        allowBlank: true,
        showDropDown: true,
        sqref: 'b2:b1000',
        formulas: [
           'asdf,fh,dfhj'
        ]
    });
 wb.write('Excel.xlsx',req);
 res.download('Excel.xlsx');
});

I am did n't get any error. excel file is also not downloading can anyone tell me am doing correct or am i made any mistake in my code.

Thanks,

via Vinoth