---
title: Container
slug: /api/container
tags:
  - module
  - public

toc_min_heading_level: 2
toc_max_heading_level: 5
---

import Type from '@site/docs/api/components/type';

# Container

:::info

Current state: **Stable**

:::

The container module permits to generate containers.

## Module: container

### class Container

### `new Container()`

- Returns: <Type>Container</Type>

```javascript
const container = new Container();

container.add('config', {
  get: (configName) => {},
  set: (configName, value) => {},
});

const dbConfig = container.get('config').get('database');
```

### `container.add(name, resolver)`

- `name`: <Type>String</Type> UID of the content
- `resolver`: <Type>Function</Type> | <Type>Any</Type>
  - As a function, the function will be executed when the first get method is called on this content. The result of this function will define the content of this UID.
  - `resolver(context, args)`
    - `context`: <Type>Container</Type> The container instance
    - `args`: <Type>Any</Type> Anything to be used by the resolver function
  - As anything else, this value will be resolved when getting this specified content through its UID.

Register a new content to be accessed inside the container. If the name is already used, it will throw an error.

```javascript
const container = new Container();

container.add('config', (container, args) => {});
// or
container.add('services', {});
```

### `container.get(name, args)`

- `name`: <Type>String</Type> UID of the content
- `args`: <Type>Any</Type> Value that will be passed to the resolver (if function)

Get the value stored for a specific `name`.

```javascript
const container = new Container();

container.add('config', { db: 'sqlite' });

const config = container.get('config');
// config.db === 'sqlite'
```

⚠️ If the **resolver**, used in the register function, is a **function**, the value will be the result of this resolver function with `args` as parameter on the first call to `get`.

Please pay attention that the resolver result value isn't awaited. So if resolver returns a promise, the value stored will be a promise.

```javascript
const container = new Container();

container.add('boolean', (bool) => bool);

// First call - The value is resolved through the resolver above "(bool) => bool"
container.get('boolean', true);
// true

// Any further call will use the previously set value
container.get('boolean');
// true

// Even if we try to push a new value
container.get('boolean', false);
// true
```
