---
title: Electron
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summary: Embedded NodeJS + Chromium
---
import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';
The [NodeJS Module](/docs/getting-started/installation/nodejs) can be imported
from the main or the renderer thread.
Electron presents a `fs` module. The `require('xlsx')` call loads the CommonJS
module, so `XLSX.readFile` and `XLSX.writeFile` work in the renderer thread.
This demo was tested on 2022 November 07 with Electron 21.2.2 on `darwin-x64`.
<details><summary><b>Complete Example</b> (click to show)</summary>
This demo includes a drag-and-drop box as well as a file input box, mirroring
the [SheetJS Data Preview Live Demo](https://oss.sheetjs.com/sheetjs/)
The core data in this demo is an editable HTML table. The readers build up the
table using `sheet_to_html` (with `editable:true` option) and the writers scrape
the table using `table_to_book`.
The demo project is wired for `electron-forge` to build the standalone binary.
1) Download the demo files:
- [`package.json`](pathname:///electron/package.json) : project structure
- [`main.js`](pathname:///electron/main.js) : main process script
- [`index.html`](pathname:///electron/index.html) : window page
- [`index.js`](pathname:///electron/index.js) : script loaded in render context
:::caution
Right-click each link and select "Save Link As...". Left-clicking a link will
try to load the page in your browser. The goal is to save the file contents.
:::
2) Run `npm install` to install dependencies.
3) To verify the app works, run in the test environment:
```bash
npx -y electron .
```
The app will show and you should be able to verify reading and writing by using
the relevant buttons to open files and clicking the export button.
4) To build a standalone app, run the builder:
```bash
npm run make
```
This will generate the standalone app in the `out\sheetjs-electron-...` folder.
For a recent Intel Mac, the path will be `out/sheetjs-electron-darwin-x64/`
</details>
### Writing Files
[`XLSX.writeFile`](/docs/api/write-options) writes workbooks to the file system.
`showSaveDialog` shows a Save As dialog and returns the selected file name:
```js
/* from the renderer thread */
const electron = require('@electron/remote');
/* this function will show the save dialog and try to write the workbook */
async function exportFile(workbook) {
/* show Save As dialog */
const result = await electron.dialog.showSaveDialog({
title: 'Save file as',
filters: [{
name: "Spreadsheets",
extensions: ["xlsx", "xls", "xlsb", /* ... other formats ... */]
}]
});
/* write file */
// highlight-next-line
XLSX.writeFile(workbook, result.filePath);
}
```
:::note
In older versions of Electron, `showSaveDialog` returned the path directly:
```js
var dialog = require('electron').remote.dialog;
function exportFile(workbook) {
var result = dialog.showSaveDialog();
XLSX.writeFile(workbook, result);
}
```
:::
### Reading Files
Electron offers 3 different ways to read files, two of which use Web APIs.
**File Input Element**
File input elements automatically map to standard Web APIs.
For example, assuming a file input element on the page:
```html
<input type="file" name="xlfile" id="xlf" />
```
The event handler would process the event as if it were a web event:
```js
async function handleFile(e) {
const file = e.target.files[0];
const data = await file.arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);
/* DO SOMETHING WITH workbook HERE */
}
document.getElementById("xlf").addEventListener("change", handleFile, false);
```
**Drag and Drop**
The [drag and drop snippet](/docs/solutions/input#example-user-submissions)
applies to DIV elements on the page.
For example, assuming a DIV on the page:
```html
<div id="drop">Drop a spreadsheet file here to see sheet data</div>
```
The event handler would process the event as if it were a web event:
```js
async function handleDrop(e) {
e.stopPropagation();
e.preventDefault();
const file = e.dataTransfer.files[0];
const data = await file.arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);
/* DO SOMETHING WITH workbook HERE */
}
document.getElementById("drop").addEventListener("drop", handleDrop, false);
```
**Electron API**
[`XLSX.readFile`](/docs/api/parse-options) reads workbooks from the file system.
`showOpenDialog` shows a Save As dialog and returns the selected file name.
Unlike the Web APIs, the `showOpenDialog` flow can be initiated by app code:
```js
/* from the renderer thread */
const electron = require('@electron/remote');
/* this function will show the open dialog and try to parse the workbook */
async function importFile() {
/* show Save As dialog */
const result = await electron.dialog.showOpenDialog({
title: 'Select a file',
filters: [{
name: "Spreadsheets",
extensions: ["xlsx", "xls", "xlsb", /* ... other formats ... */]
}]
});
/* result.filePaths is an array of selected files */
if(result.filePaths.length == 0) throw new Error("No file was selected!");
// highlight-next-line
return XLSX.readFile(result.filePaths[0]);
}
```
:::note
In older versions of Electron, `showOpenDialog` returned the path directly:
```js
var dialog = require('electron').remote.dialog;
function importFile(workbook) {
var result = dialog.showOpenDialog({ properties: ['openFile'] });
return XLSX.readFile(result[0]);
}
```
:::
### Electron Breaking Changes
The first version of this demo used Electron 1.7.5. The current demo includes
the required changes for Electron 19.2.2.
There are no Electron-specific workarounds in the library, but Electron broke
backwards compatibility multiple times. A summary of changes is noted below.
:::caution
Electron 6.x changed the `dialog` API. Methods like `showSaveDialog` originally
returned an array of strings, but now returns a `Promise`. This change was not
documented.
Electron 9.0.0 and later require the preference `nodeIntegration: true` in order
to `require('xlsx')` in the renderer process.
Electron 12.0.0 and later also require `worldSafeExecuteJavascript: true` and
`contextIsolation: true`.
Electron 14+ must use `@electron/remote` instead of `remote`. An `initialize`
call is required to enable Developer Tools in the window.
:::