> For the complete documentation index, see [llms.txt](https://docs.create-scandipwa-app.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.create-scandipwa-app.com/extensions/extensions.md).

# Extensions

The project introduces the concept of "extensions".

{% hint style="info" %}
**Extension** - is a reusable, isolated part of your application. It can contain presentation layer, business logic or even build configuration.
{% endhint %}

For NPM package to be considered an extension, it must have a `package.json` field `scandipwa.type` equal to `extension`. For example:

```javascript
{
    "scandipwa": {
        "type": "extension"
    }
    ...
}
```

The **extensions are power-less without a theme**. The application compiles from a theme sources. Extensions are just an isolated pieces, which make some features of your application work.

{% hint style="info" %}
Any package containing the `@namespace` magic comments **must** have a `scandipwa` block declared in its package.json file. Otherwise, the `@namespace` magic comments will not be handled correctly during the build time, hence will not work.
{% endhint %}

## Registering an extension

**Both themes and extensions can register extensions**. In order to do it, the extension should be added to `scandipwa.extensions` object of `package.json` . The extension must be a valid NPM package, therefore you are required to add it into `dependencies` field of your `package.json`. Like so:

```javascript
{
    "dependencies": {
        "@scandipwa/m2-theme": "0.0.2",
        ...
    },
    "scandipwa": {
        "extensions": {
            "@scandipwa/m2-theme": true
        },
        ...
    }
    ...
}
```

This process could be automated using [ScandiPWA CLI](https://docs.scandipwa.com/developing-with-scandi/developer-tools/scandipwa-cli). First, make sure you are in your theme's root folder. Now, to install an extension from NPM registry, you can use following command:

```javascript
scandipwa extension install <PACKAGE>
```

In order to create new extension, use following command:

```javascript
scandipwa extension create <PACKAGE>
```

{% hint style="info" %}
This command will create a new extension in the `packages` folder and register it in your current theme. It will be symlinked from `packages` to proper folder under `node_modules`.
{% endhint %}

## Enabling an extension

Enabling and disabling an extension is achieved by setting the `true`or `false` as a value of the extension key in `scandipwa.extensions` . Your theme can control enabled extensions across the whole application. This allows to disable the previously enabled extension. The sequence of preference in this case is:

1. Your theme enabled extensions
2. Your theme's parent themes enabled extensions
3. Extension enabled extensions

{% hint style="danger" %}

### Watch out!

Disabling a previously enabled extension can lead to layout-shifts and issues inside of your parent theme. Also, there might be extensions plugging into the extension you intend to disable, this can lead to unexpected results.
{% endhint %}

## Extension features

Extensions are very important and powerful part of ScandiPWA tool-chain. Following feature are available:

* [Application plugins](/extensions/application-plugins.md)
* [Build configuration plugins](/extensions/build-configuration-plugins.md)
* [Module preference](/extensions/virtual-modules.md)
* [File provision](/extensions/file-provision.md)

Following features are upcoming in next versions of Create ScandiPWA App releases:

* Translation bundles
* HTML template plugin

##