To handle Excel files in Node.js, install the node-xlsx package using npm.

npm install node-xlsx

The node-xlsx library proivdes two primary functions: parse() for reading Excel files and build() for creating them. The parse() method accepts a file path and returns an array of objects representing the workbook's sheets.

To convert an Excel file into a JSON structure, the following code reads the first worksheet and maps the data rows to objects using the first row as proeprty names.

const xlsx = require('node-xlsx');
const fs = require('fs');

// Load and parse the spreadsheet file
const sheets = xlsx.parse('./origin.xlsx');
const firstSheetData = sheets[0].data;

// Extract column headers and data rows
const headers = firstSheetData[0];
const dataRows = firstSheetData.slice(1);

// Convert each row into an object
const jsonResult = dataRows.map(row => {
    const rowObject = {};
    row.forEach((cellValue, columnIndex) => {
        rowObject[headers[columnIndex]] = cellValue;
    });
    return rowObject;
});

// Save the result as a JSON file
fs.writeFileSync('./output.json', JSON.stringify(jsonResult, null, 2));
console.log('Conversion completed successfully.');

Execute the script with Node.js to generate the output.json file containing the structured data.