There are a few different libraries doing parsing of Excel files (.xlsx). I will list two projects I find interesting and worth looking into.

Node-xlsx

Excel parser and builder. It's kind of a wrapper for a popular project JS-XLSX, which is a pure javascript implementation from the Office Open XML spec.

node-xlsx project page

Example for parsing file

var xlsx = require('node-xlsx');

var obj = xlsx.parse(__dirname + '/myFile.xlsx'); // parses a file

var obj = xlsx.parse(fs.readFileSync(__dirname + '/myFile.xlsx')); // parses a buffer

ExcelJS

Read, manipulate and write spreadsheet data and styles to XLSX and JSON. It's an active project. At the time of writing the latest commit was 9 hours ago. I haven't tested this myself, but the api looks extensive with a lot of possibilites.

exceljs project page

Code example:

// read from a file
var workbook = new Excel.Workbook();
workbook.xlsx.readFile(filename)
    .then(function() {
        // use workbook
    });

// pipe from stream
var workbook = new Excel.Workbook();
stream.pipe(workbook.xlsx.createInputStream());

You can also use this node module called js-xlsx

1) Install module
npm install xlsx

2) Import module + code snippet

var XLSX = require('xlsx')
var workbook = XLSX.readFile('Master.xlsx');
var sheet_name_list = workbook.SheetNames;
var xlData = XLSX.utils.sheet_to_json(workbook.Sheets[sheet_name_list[0]]);
console.log(xlData);

install exceljs and use the following code,

var Excel = require('exceljs');

var wb = new Excel.Workbook();
var path = require('path');
var filePath = path.resolve(__dirname,'sample.xlsx');

wb.xlsx.readFile(filePath).then(function(){

    var sh = wb.getWorksheet("Sheet1");

    sh.getRow(1).getCell(2).value = 32;
    wb.xlsx.writeFile("sample2.xlsx");
    console.log("Row-3 | Cell-2 - "+sh.getRow(3).getCell(2).value);

    console.log(sh.rowCount);
    //Get all the rows data [1st and 2nd column]
    for (i = 1; i <= sh.rowCount; i++) {
        console.log(sh.getRow(i).getCell(1).value);
        console.log(sh.getRow(i).getCell(2).value);
    }
});

You can use read-excel-file npm.

In that, you can specify JSON Schema to convert XLSX into JSON Format.

const readXlsxFile = require('read-excel-file/node');

const schema = {
    'Segment': {
        prop: 'Segment',
        type: String
    },
    'Country': {
        prop: 'Country',
        type: String
    },
    'Product': {
        prop: 'Product',
        type: String
    }
}

readXlsxFile('sample.xlsx', { schema }).then(({ rows, errors }) => {
    console.log(rows);
});