sheetjs/demos/react/README.md

# React

The `xlsx.core.min.js` and `xlsx.full.min.js` scripts are designed to be dropped
into web pages with script tags:

```html
<script src="xlsx.full.min.js"></script>
```

The library can also be imported directly from JSX code with:

```js
import { read, utils, writeFileXLSX } from 'xlsx';
```

This demo shows a simple React component transpiled in the browser using Babel
standalone library.  Since there is no standard React table model, this demo
settles on the array of arrays approach.


Other scripts in this demo show:
- server-rendered React component (with `next.js`)
- `react-native` deployment for iOS and android
- [`react-data-grid` reading, modifying, and writing files](modify/)

## How to run

Run `make react` to run the browser demo for React, or run `make next` to run
the server-rendered demo using `next.js`.

## Internal State

The simplest state representation is an array of arrays.  To avoid having the
table component depend on the library, the column labels are precomputed.  The
state in this demo is shaped like the following object:

```js
{
  cols: [{ name: "A", key: 0 }, { name: "B", key: 1 }, { name: "C", key: 2 }],
  data: [
    [ "id",    "name", "value" ],
    [    1, "sheetjs",    7262 ],
    [    2, "js-xlsx",    6969 ]
  ]
}
```

`sheet_to_json` and `aoa_to_sheet` utility functions can convert between arrays
of arrays and worksheets:

```js
/* convert from workbook to array of arrays */
var first_worksheet = workbook.Sheets[workbook.SheetNames[0]];
var data = XLSX.utils.sheet_to_json(first_worksheet, {header:1});

/* convert from array of arrays to workbook */
var worksheet = XLSX.utils.aoa_to_sheet(data);
var new_workbook = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(new_workbook, worksheet, "SheetJS");
```

The column objects can be generated with the `encode_col` utility function:

```js
function make_cols(refstr/*:string*/) {
  var o = [];
  var range = XLSX.utils.decode_range(refstr);
  for(var i = 0; i <= range.e.c; ++i) {
    o.push({name: XLSX.utils.encode_col(i), key:i});
  }
  return o;
}
```

## React Native

<img src="screen.png" width="400px"/>

Reproducing the full project is straightforward:

```bash
$ make native     # build the project
$ make ios        # build and run the iOS demo
$ make android    # build and run the android demo
```

The app will prompt before reading and after writing data.  The printed location
depends on the environment:

- android: path in the device filesystem
- iOS simulator: local path to file
- iOS device: a path accessible from iTunes App Documents view

Components used in the demo:
- [`react-native-table-component`](https://npm.im/react-native-table-component)
- [`react-native-file-access`](https://npm.im/react-native-file-access)

React Native does not provide a native component for reading and writing files.
The sample script `react-native.js` uses `react-native-file-access` and has
notes for integrations with `react-native-fetch-blob` and `react-native-fs`.

Note: for real app deployments, the `UIFileSharingEnabled` flag must be manually
set in the iOS project `Info.plist` file.

## Server-Rendered React Components with Next.js

The demo reads from `public/sheetjs.xlsx`.  HTML output is generated using
`XLSX.utils.sheet_to_html` and inserted with `dangerouslySetInnerHTML`:

```jsx
export default function Index({html, type}) { return (
  // ...
  <div dangerouslySetInnerHTML={{ __html: html }} />
  // ...
); }
```

Next currently offers 3 general strategies for server-side data fetching:

#### "Server-Side Rendering" using `getServerSideProps`

`/getServerSideProps` reads the file on each request.  The first worksheet is
converted to HTML:

```js
export async function getServerSideProps() {
  const wb = XLSX.readFile(path);
  return { props: {
    html: utils.sheet_to_html(wb.Sheets[wb.SheetNames[0]])
  }};
}
```

#### "Static Site Generation" using `getStaticProps`

`/getServerSideProps` reads the file at build time.  The first worksheet is
converted to HTML:

```js
export async function getStaticProps() {
  const wb = XLSX.readFile(path);
  return { props: {
    html: utils.sheet_to_html(wb.Sheets[wb.SheetNames[0]])
  }};
}
```

#### "Static Site Generation with Dynamic Routes" using `getStaticPaths`

`/getStaticPaths` reads the file at build time and generates a list of sheets.

`/sheets/[id]` uses `getStaticPaths` to generate a path per sheet index:

```js
export async function getStaticPaths() {
  const wb = XLSX.readFile(path);
  return {
    paths: wb.SheetNames.map((name, idx) => ({ params: { id: idx.toString()  } })),
    fallback: false
  };
}
```

It also uses `getStaticProps` for the actual HTML generation:

```js
export async function getStaticProps(ctx) {
  const wb = XLSX.readFile(path);
  return { props: {
    html: utils.sheet_to_html(wb.Sheets[wb.SheetNames[ctx.params.id]]),
  }};
}
```

## Additional Notes

Some additional notes can be found in [`NOTES.md`](NOTES.md).

[![Analytics](https://ga-beacon.appspot.com/UA-36810333-1/SheetJS/js-xlsx?pixel)](https://github.com/SheetJS/js-xlsx)