[XLSX-Renderer] Writing a file to a buffer to send as attachment

[ywaserblat-excelforce]

Is there an option in the node.js environment, to write the data to a buffer that will be sent to the front-end as an attachment via express.js? something like the writeBuffer() in the browser version.
thanks in advance!

[Seusara]

Yes — since xlsx-renderer's render methods resolve with an ExcelJS Workbook instance under the hood, workbook.xlsx.writeBuffer() is available in Node.js exactly like in the browser example. In Node it resolves to a Buffer instead of a Blob, so you can send it directly in the Express response with the right headers:

const { Renderer } = require('xlsx-renderer');

app.get('/report', async (req, res) => {
const renderer = new Renderer();
const workbook = await renderer.renderFromFile('./invoice-template.xlsx', viewModel);
const buffer = await workbook.xlsx.writeBuffer();

res.setHeader('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
res.setHeader('Content-Disposition', 'attachment; filename=report.xlsx');
res.send(buffer);
});

No need to write to a temp file on disk first. Just make sure Content-Disposition is set to attachment (not inline) so the browser downloads it instead of trying to render it, and double check res.send(buffer) is sending the raw Buffer (not JSON.stringify-ing it, which Express does automatically for Buffers so you're fine either way).