---
title: Ruby + Bindings
pagination_prev: demos/bigdata/index
pagination_next: solutions/input
---

import current from '/version.js';
import CodeBlock from '@theme/CodeBlock';

ExecJS is a Ruby abstraction over a number of JS runtimes including V8.

The [SheetJS Standalone scripts](/docs/getting-started/installation/standalone)
can be parsed and evaluated in every supported runtime.

## Integration Details

_Load SheetJS Scripts_

The main library can be loaded and compiled in a new context:

```rb
require "execjs"

source = File.open("xlsx.full.min.js", "rb").read;
source.force_encoding("UTF-8");
context = ExecJS.compile(source);
```

To confirm the library is loaded, `XLSX.version` can be inspected:

```rb
puts context.eval("XLSX.version");
```

_Reading and Writing Files_

The architecture of ExecJS forces users to combine reading and writing in one
function step.  Base64 strings should be used for interchange.  For example,
the following snippet reads data from `pres.numbers`, generates an XLSB file,
and writes to `sheetjsw.xlsb`:

```rb
require "base64"

# read and encode data to Base64
data = Base64.strict_encode64(File.open("pres.numbers", "rb").read);

# define function and call with the data
xlsb = context.call(<<EOF, data);
function(data) {
  /* parse data -- the argument is the data from Ruby code */
  var wb = XLSX.read(data, {type: 'base64'});
  /* write XLSB data (encoded as base64) */
  return XLSX.write(wb, {bookType: "xlsb", type: "base64"});
}
EOF
# at this point, `xlsb` is a Base64-encoded string

# decode and write to file
File.write("sheetjsw.xlsb", Base64.strict_decode64(xlsb), mode: "wb");
```

The `strict_` variants ensure that no newlines are added to the strings.

## Complete Example

:::note Tested Deployments

This demo was tested in the following deployments:

| Platform     | Ruby     | ExecJS  | Date       |
|:-------------|:---------|:--------|:-----------|
| `darwin-x64` | `2.6.10` | `2.9.1` | 2024-04-25 |
| `darwin-arm` | `2.6.10` | `2.9.1` | 2023-12-01 |
| `win10-x64`  | `3.2.3`  | `2.9.1` | 2024-03-10 |
| `win11-arm`  | `3.0.2`  | `2.9.1` | 2023-12-01 |
| `linux-x64`  | `3.0.5`  | `2.9.1` | 2024-03-21 |
| `linux-arm`  | `2.7.4`  | `2.9.1` | 2023-12-01 |

**Note: The Windows 11 ARM64 test used the Ruby version that ships with WSL.**

:::

0) Install Ruby, `gem` (RubyGems), and the dependencies:

```bash
gem install execjs
```

<details>
  <summary><b>Installation Notes</b> (click to show)</summary>

The command may need to be run as an administrator or root user:

```bash
sudo gem install execjs
```

:::note pass

On Arch Linux-based platforms including the Steam Deck, `rubygems` must be
installed through the package manager:

```bash
sudo pacman -Syu rubygems
```

:::

</details>

1) Create a new project folder:

```bash
mkdir sheetjs-rb
cd sheetjs-rb
```

2) Download the SheetJS Standalone script and the test file. Save both files in
the project directory:

<ul>
<li><a href={`https://cdn.sheetjs.com/xlsx-${current}/package/dist/xlsx.full.min.js`}>xlsx.full.min.js</a></li>
<li><a href="https://docs.sheetjs.com/pres.numbers">pres.numbers</a></li>
</ul>

<CodeBlock language="bash">{`\
curl -LO https://cdn.sheetjs.com/xlsx-${current}/package/dist/xlsx.full.min.js
curl -LO https://docs.sheetjs.com/pres.numbers`}
</CodeBlock>

3) Download [`ExecSheetJS.rb`](pathname:///execjs/ExecSheetJS.rb):

```bash
curl -LO https://docs.sheetjs.com/execjs/ExecSheetJS.rb
```

4) Run the demo:

```bash
ruby ExecSheetJS.rb pres.numbers
```

If the program succeeded, the CSV contents will be printed to console and the
file `sheetjsw.xlsb` will be created.  That file can be opened with Excel.

:::caution pass

If a JavaScript runtime is not available, the script will throw an error:

```
execjs/runtimes.rb:68:in `autodetect': Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
```

ExecJS 2.9.1 supports the Bun runtime. Install the Bun runtime[^1], restart the
terminal, and re-run the script.

:::

[^1]: `curl -fsSL https://bun.sh/install | bash` can be run from macOS, Linux, and Windows WSL.