# AssetBundle

> AssetBundle represents a collection of asset files, such as CSS, JS, images.

[API reference](/docs/api/index.md) › [yii](/docs/api/yii/index.md) › [web](/docs/api/yii/web/index.md) › AssetBundle

| class | `yii\web\AssetBundle` |
| --- | --- |
| Extends | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| Implements | [`yii\base\Configurable`](/docs/api/yii/base/configurable/index.md) |
| Since | 2.0 |
| Source | [`framework/web/AssetBundle.php`](https://github.com/yiisoft/yii2/blob/22.0/framework/web/AssetBundle.php#L35) |

14 subclasses:

- [`yii\captcha\CaptchaAsset`](/docs/api/yii/captcha/captchaasset/index.md)
- [`yii\grid\GridViewAsset`](/docs/api/yii/grid/gridviewasset/index.md)
- [`yii\validators\PunycodeAsset`](/docs/api/yii/validators/punycodeasset/index.md)
- [`yii\validators\ValidationAsset`](/docs/api/yii/validators/validationasset/index.md)
- [`JqueryAsset`](/docs/api/yii/web/jqueryasset/index.md)
- [`YiiAsset`](/docs/api/yii/web/yiiasset/index.md)
- [`yii\widgets\ActiveFormAsset`](/docs/api/yii/widgets/activeformasset/index.md)
- [`yii\widgets\MaskedInputAsset`](/docs/api/yii/widgets/maskedinputasset/index.md)
- [`yii\widgets\PjaxAsset`](/docs/api/yii/widgets/pjaxasset/index.md)
- [`yii2\extensions\bootstrap6\asset\AbstractNpmAsset`](/docs/extensions/bootstrap6/reference/asset/abstractnpmasset/index.md)
- [`yii2\extensions\filepond\asset\AbstractLocalAsset`](/docs/extensions/filepond/reference/asset/abstractlocalasset/index.md)
- [`yii2\extensions\filepond\asset\AbstractNpmAsset`](/docs/extensions/filepond/reference/asset/abstractnpmasset/index.md)
- [`yii\debug\DebugAsset`](/docs/extensions/debug/reference/debugasset/index.md)
- [`yii\debug\ToolbarAsset`](/docs/extensions/debug/reference/toolbarasset/index.md)

AssetBundle represents a collection of asset files, such as CSS, JS, images.

Each asset bundle has a unique name that globally identifies it among all asset bundles used in an application.
The name is the [fully qualified class name](https://www.php.net/manual/en/language.namespaces.rules.php)
of the class representing it.

An asset bundle can depend on other asset bundles. When registering an asset bundle
with a view, all its dependent asset bundles will be automatically registered.

For more details and usage information on AssetBundle, see the [guide article on assets](/docs/guide/structure-assets/index.md).

## Properties

| Property | Type | Description | Defined by |
| --- | --- | --- | --- |
| [`$basePath`](#property-basePath) | `string\|null` | The Web-accessible directory that contains the asset files in this bundle. Default: `null`. | `AssetBundle` |
| [`$baseUrl`](#property-baseUrl) | `string\|null` | The base URL for the relative asset files listed in [`$js`](/docs/api/yii/web/assetbundle/index.md#property-js) and [`$css`](/docs/api/yii/web/assetbundle/index.md#property-css). Default: `null`. | `AssetBundle` |
| [`$css`](#property-css) | `array<string\|array<array-key, mixed>>` | List of CSS files that this bundle contains. Default: `[]`. | `AssetBundle` |
| <span id="property-cssOptions"></span>`$cssOptions` | `yii\web\RegisterCssFileOptions` | The options that will be passed to [`View::registerCssFile()`](/docs/api/yii/web/view/index.md#method-registerCssFile) when registering the CSS files in this bundle. Default: `[]`. | `AssetBundle` |
| [`$depends`](#property-depends) | `array<class-string>` | List of bundle class names that this bundle depends on. Default: `[]`. | `AssetBundle` |
| [`$js`](#property-js) | `array<string\|array<array-key, mixed>>` | List of JavaScript files that this bundle contains. Default: `[]`. | `AssetBundle` |
| <span id="property-jsOptions"></span>`$jsOptions` | `yii\web\RegisterJsFileOptions` | The options that will be passed to [`View::registerJsFile()`](/docs/api/yii/web/view/index.md#method-registerJsFile) when registering the JS files in this bundle. Default: `[]`. | `AssetBundle` |
| [`$publishOptions`](#property-publishOptions) | `yii\web\PublishOptions` | The options to be passed to [`AssetManager::publish()`](/docs/api/yii/web/assetmanager/index.md#method-publish) when the asset bundle is being published. Default: `[]`. | `AssetBundle` |
| [`$sourcePath`](#property-sourcePath) | `string\|null` | The directory that contains the source asset files for this asset bundle. Default: `null`. | `AssetBundle` |

## Methods

| Method | Description | Defined by |
| --- | --- | --- |
| <span id="method-__construct"></span>[`__construct()`](/docs/api/yii/base/baseobject/index.md#method-__construct) | Constructor. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-__call"></span>[`__call()`](/docs/api/yii/base/baseobject/index.md#method-__call) | Calls the named method which is not a class method. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-__get"></span>[`__get()`](/docs/api/yii/base/baseobject/index.md#method-__get) | Returns the value of an object property. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-__isset"></span>[`__isset()`](/docs/api/yii/base/baseobject/index.md#method-__isset) | Checks if a property is set, i.e. defined and not null. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-__set"></span>[`__set()`](/docs/api/yii/base/baseobject/index.md#method-__set) | Sets value of an object property. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-__unset"></span>[`__unset()`](/docs/api/yii/base/baseobject/index.md#method-__unset) | Sets an object property to null. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-canGetProperty"></span>[`canGetProperty()`](/docs/api/yii/base/baseobject/index.md#method-canGetProperty) | Returns a value indicating whether a property can be read. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-canSetProperty"></span>[`canSetProperty()`](/docs/api/yii/base/baseobject/index.md#method-canSetProperty) | Returns a value indicating whether a property can be set. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-className"></span>[`className()`](/docs/api/yii/base/baseobject/index.md#method-className) static | Returns the fully qualified name of this class. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-hasMethod"></span>[`hasMethod()`](/docs/api/yii/base/baseobject/index.md#method-hasMethod) | Returns a value indicating whether a method is defined. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-hasProperty"></span>[`hasProperty()`](/docs/api/yii/base/baseobject/index.md#method-hasProperty) | Returns a value indicating whether a property is defined. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| [`init()`](#method-init) | Initializes the bundle. | `AssetBundle` |
| [`publish()`](#method-publish) | Publishes the asset bundle if its source code is not under Web-accessible directory. | `AssetBundle` |
| [`register()`](#method-register) static | Registers this asset bundle with a view. | `AssetBundle` |
| [`registerAssetFiles()`](#method-registerAssetFiles) | Registers the CSS and JS files with the given view. | `AssetBundle` |

## Property details

### $basePath <span id="property-basePath"></span>

```php
public string|null $basePath = null
```

The Web-accessible directory that contains the asset files in this bundle.

If [`$sourcePath`](/docs/api/yii/web/assetbundle/index.md#property-sourcePath) is set, this property will be *overwritten* by [`AssetManager`](/docs/api/yii/web/assetmanager/index.md)
when it publishes the asset files from [`$sourcePath`](/docs/api/yii/web/assetbundle/index.md#property-sourcePath).

You can use either a directory or an alias of the directory.

### $baseUrl <span id="property-baseUrl"></span>

```php
public string|null $baseUrl = null
```

The base URL for the relative asset files listed in [`$js`](/docs/api/yii/web/assetbundle/index.md#property-js) and [`$css`](/docs/api/yii/web/assetbundle/index.md#property-css).

If [`$sourcePath`](/docs/api/yii/web/assetbundle/index.md#property-sourcePath) is set, this property will be *overwritten* by [`AssetManager`](/docs/api/yii/web/assetmanager/index.md)
when it publishes the asset files from [`$sourcePath`](/docs/api/yii/web/assetbundle/index.md#property-sourcePath).

You can use either a URL or an alias of the URL.

### $css <span id="property-css"></span>

```php
public array<string|array<array-key, mixed>> $css = []
```

List of CSS files that this bundle contains.

Each CSS file can be specified
in one of the three formats as explained in [`$js`](/docs/api/yii/web/assetbundle/index.md#property-js).

Note that only a forward slash "/" should be used as directory separator.

### $depends <span id="property-depends"></span>

```php
public array<class-string> $depends = []
```

List of bundle class names that this bundle depends on.

For example:

```
public $depends = [
   'yii\web\YiiAsset',
   'yii\bootstrap\BootstrapAsset',
];
```

### $js <span id="property-js"></span>

```php
public array<string|array<array-key, mixed>> $js = []
```

List of JavaScript files that this bundle contains.

Each JavaScript file can be
specified in one of the following formats:

- an absolute URL representing an external asset. For example,
  `https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js` or
  `//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js`.
- a relative path representing a local asset (e.g. `js/main.js`). The actual file path of a local
  asset can be determined by prefixing [`$basePath`](/docs/api/yii/web/assetbundle/index.md#property-basePath) to the relative path, and the actual URL
  of the asset can be determined by prefixing [`$baseUrl`](/docs/api/yii/web/assetbundle/index.md#property-baseUrl) to the relative path.
- an array, with the first entry being the URL or relative path as described before, and a list of key => value pairs
  that will be used to overwrite [`$jsOptions`](/docs/api/yii/web/assetbundle/index.md#property-jsOptions) settings for this entry.
  This functionality is available since version 2.0.7.

Note that only a forward slash "/" should be used as directory separator.

### $publishOptions <span id="property-publishOptions"></span>

```php
public yii\web\PublishOptions $publishOptions = []
```

The options to be passed to [`AssetManager::publish()`](/docs/api/yii/web/assetmanager/index.md#method-publish) when the asset bundle is being published.

This property is used only when [`$sourcePath`](/docs/api/yii/web/assetbundle/index.md#property-sourcePath) is set.

### $sourcePath <span id="property-sourcePath"></span>

```php
public string|null $sourcePath = null
```

The directory that contains the source asset files for this asset bundle.

A source asset file is a file that is part of your source code repository of your Web application.

You must set this property if the directory containing the source asset files is not Web accessible.
By setting this property, [`AssetManager`](/docs/api/yii/web/assetmanager/index.md) will publish the source asset files
to a Web-accessible directory automatically when the asset bundle is registered on a page.

If you do not set this property, it means the source asset files are located under [`$basePath`](/docs/api/yii/web/assetbundle/index.md#property-basePath).

You can use either a directory or an alias of the directory.

## Method details

### init() <span id="method-init"></span>

```php
public function init(): mixed
```

Initializes the bundle.

If you override this method, make sure you call the parent implementation in the last.

**Returns**

`mixed`

### publish() <span id="method-publish"></span>

```php
public function publish(yii\web\AssetManager $am): mixed
```

Publishes the asset bundle if its source code is not under Web-accessible directory.

It will also try to convert non-CSS or JS files (e.g. LESS, Sass) into the corresponding
CSS or JS files using [asset converter](/docs/api/yii/web/assetmanager/index.md#property-converter).

**Parameters**

| Parameter | Type | Description |
| --- | --- | --- |
| `$am` | [`AssetManager`](/docs/api/yii/web/assetmanager/index.md) | The asset manager to perform the asset publishing |

**Returns**

`mixed`

### register() <span id="method-register"></span>

```php
public static function register(yii\web\View $view): static
```

Registers this asset bundle with a view.

**Parameters**

| Parameter | Type | Description |
| --- | --- | --- |
| `$view` | [`View`](/docs/api/yii/web/view/index.md) | The view to be registered with |

**Returns**

`static`: The registered asset bundle instance

### registerAssetFiles() <span id="method-registerAssetFiles"></span>

```php
public function registerAssetFiles(yii\web\View $view): mixed
```

Registers the CSS and JS files with the given view.

**Parameters**

| Parameter | Type | Description |
| --- | --- | --- |
| `$view` | [`View`](/docs/api/yii/web/view/index.md) | The view that the asset files are to be registered with. |

**Returns**

`mixed`