[//]: #@corifeus-header [](https://www.npmjs.com/package/p3x-json2xls-worker-thread) [](https://paypal.me/patrikx3) [](https://www.patrikx3.com/en/front/contact) [](https://www.facebook.com/corifeus.software) [](https://network.corifeus.com/status/31ad7a5c194347c33e5445dbaf8) # 📈 Convert JSON to Excel XLSX with offloading the constructing the data using a worker thread v2026.4.133 🌌 **Bugs are evident™ - MATRIX️** 🚧 **This project is under active development!** 📢 **We welcome your feedback and contributions.** ### NodeJS LTS is supported ### 🛠️ Built on NodeJs version ```txt v24.14.1 ``` # 📝 Description [//]: #@corifeus-header:end Utility to convert json to an excel file, based on [Node-Excel-Export](https://github.com/functionscope/Node-Excel-Export) using a worker thread by not blocking the NodeJs event loop using `async` functions and options. This is a totally fork of the [json2xls](https://github.com/rikkertkoppes/json2xls), but the XLSX constructing can be CPU intensive so we are offloading the XLSX constructing using a worker thread. Of course, when using a worker thread, the execution is about 20-25ms longer, than when we are in the event loop, so the worker thread is valid when we are generating a big dataset. # Installation ```bash npm install p3x-json2xls-worker-thread ``` # Usage Use to save as file: ```js const json2xls = require('p3x-json2xls-worker-thread') const fs = require('fs').promises const json = { foo: 'bar', qux: 'moo', poo: 123, stux: new Date() } const executAsync = async() => { try { // let nodeExcelOptions = undefined /* The following options are supported: - style: a styles xml file, see <https://github.com/functionscope/Node-Excel-Export> - fields: either an array or map containing field configuration: - array: a list of names of fields to be exported, in that order - object: a map of names of fields to be exported and the types of those fields. Supported types are 'number','string','bool' */ if (ifSomeConditionIsTrue) { nodeExcelOptions = { fields: ['poo'] } } const options = { output: 'binary' /* default */ || 'base64', nodeExcel: nodeExcelOptions } const xlsBinary = await json2xls(json, options) await fs.writeFile('data.xlsx', xlsBinary, 'binary'); } catch(e) { // handle error console.error(e) } } executAsync() ``` Or use as express middleware. It adds a convenience `xls` method to the response object to immediately output an excel as download. ```js const json2xls = require('p3x-json2xls-worker-thread') const jsonArr = [{ foo: 'bar', qux: 'moo', poo: 123, stux: new Date() }, { foo: 'bar', qux: 'moo', poo: 345, stux: new Date() }]; app.use(json2xls.middleware); app.get('/',function(req, res) { res.xls('data.xlsx', jsonArr); }); ``` It is possible to block the event loop by using the `sync` function eg.: ```js const json2xls = require('p3x-json2xls-worker-thread') const json = { foo: 'bar', qux: 'moo', poo: 123, stux: new Date() } const xlsBinary = json2xls.sync(json, { output: 'base64' // can be binary as well, just sugar... }) console.log(xlsBinary) ``` [//]: #@corifeus-footer --- # 🌐 Meet Assistant SaaS — meeting.corifeus.com Don't want to install anything? 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[**P3X-JSON2XLS-WORKER-THREAD**](https://corifeus.com/json2xls-worker-thread) Build v2026.4.133 [](https://www.npmjs.com/package/p3x-json2xls-worker-thread) [](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=QZVM4V6HVZJW6) [](https://www.patrikx3.com/en/front/contact) [](https://www.facebook.com/corifeus.software) [//]: #@corifeus-footer:end