---
title: NW.js
pagination_prev: demos/mobile/index
pagination_next: demos/cli/index
sidebar_position: 2
sidebar_custom_props:
summary: Embedded Chromium + NodeJS
---
import current from '/version.js';
import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';
import CodeBlock from '@theme/CodeBlock';
The [SheetJS Standalone scripts](/docs/getting-started/installation/standalone)
can be referenced in a `SCRIPT` tag from the entry point HTML page.
The "Complete Example" creates an app that looks like the screenshots below:
<table><thead><tr>
<th><a href="#complete-example">Windows</a></th>
<th><a href="#complete-example">macOS</a></th>
<th><a href="#complete-example">Linux</a></th>
</tr></thead><tbody><tr><td>
</td><td>
</td><td>
</td></tr></tbody></table>
## Integration Details
NW.js provides solutions for reading and writing files.
### Reading Files
The standard HTML5 `FileReader` techniques from the browser apply to NW.js!
NW.js handles the OS minutiae for dragging files into app windows. The
[drag and drop snippet](/docs/solutions/input#example-user-submissions) apply
to DIV elements on the page.
Similarly, 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);
```
### Writing Files
File input elements with the attribute `nwsaveas` show UI for saving a file. The
standard trick is to generate a hidden file input DOM element and "click" it.
Since NW.js does not present a `writeFileSync` in the `fs` package, a manual
step is required:
```js
/* pre-build the hidden nwsaveas input element */
var input = document.createElement('input');
input.style.display = 'none';
input.setAttribute('nwsaveas', 'SheetJSNWDemo.xlsx');
input.setAttribute('type', 'file');
document.body.appendChild(input);
/* show a message if the save is canceled */
input.addEventListener('cancel',function(){ alert("Save was canceled!"); });
/* write to a file on the 'change' event */
input.addEventListener('change',function(e){
/* the `value` is the path that the program will write */
var filename = this.value;
/* use XLSX.write with type "buffer" to generate a buffer" */
/* highlight-next-line */
var wbout = XLSX.write(workbook, {type:'buffer', bookType:"xlsx"});
/* highlight-next-line */
require("fs").writeFile(filename, wbout, function(err) {
if(!err) return alert("Saved to " + filename);
alert("Error: " + (err.message || err));
});
});
input.click();
```
## Complete Example
:::note Tested Deployments
This demo was tested in the following environments:
| OS and Version | Architecture | NW.js | Date | Notes |
|:---------------|:-------------|:---------|:-----------|:---------------------|
| macOS 14.3.1 | `darwin-x64` | `0.85.0` | 2024-03-12 | |
| macOS 14.5 | `darwin-arm` | `0.88.0` | 2024-05-28 | |
| Windows 10 | `win10-x64` | `0.83.0` | 2024-03-04 | |
| Windows 11 | `win11-arm` | `0.88.0` | 2024-05-28 | |
| Linux (HoloOS) | `linux-x64` | `0.89.0` | 2024-07-07 | |
| Linux (Debian) | `linux-arm` | `0.60.0` | 2024-05-23 | Unofficial build[^1] |
:::
0) Create a project folder:
```bash
mkdir sheetjs-nwjs
cd sheetjs-nwjs
```
1) Create a `package.json` file that specifies the entry point:
<CodeBlock language="json" title="package.json">{`\
{
"name": "sheetjs-nwjs",
"author": "sheetjs",
"version": "0.0.0",
"main": "index.html",
"dependencies": {
"nw": "0.89.0",
"xlsx": "https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz"
}
}`}
</CodeBlock>
2) Download [`index.html`](pathname:///nwjs/index.html) into the same folder.
:::caution pass
Right-click the link and select "Save Link As...". Left-clicking the link will
try to load the page in your browser. The goal is to save the file contents.
:::
In the terminal window, the download can be performed with:
```bash
curl -LO https://docs.sheetjs.com/nwjs/index.html
```
3) Install dependencies:
```bash
npm i
```
4) To verify the app works, run in the test environment:
```bash
npx nw .
```
On launch, the app will fetch and parse https://docs.sheetjs.com/pres.numbers .
Using the file input element, a file can be selected from the filesystem and the
table will refresh with the contents of the selected file.
Click "Export Data!" and save the generated file to `SheetJSNWDemo.xlsx`. This
file can be opened in Excel or another spreadsheet editor.
5) To build a standalone app, run the builder:
```bash
npx -p nw-builder nwbuild --mode=build --version=0.89.0 --glob=false --outDir=../out ./
```
This will generate the standalone app in the `..\out\` folder.
6) Launch the generated application:
| Architecture | Command |
|:-------------|:--------------------------------------------------------------|
| `linux-x64` | `../out/sheetjs-nwjs` |
[^1]: The [`nw60-arm64_2022-01-08` release](https://github.com/LeonardLaszlo/nw.js-armv7-binaries/releases/tag/nw60-arm64_2022-01-08) included an ARM64 version of `nw`.