> For the complete documentation index, see [llms.txt](https://docs.hackle.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hackle.io/en/development-guide/nodejs.md).

# Node.js

{% hint style="success" %}
In Node.js, you can integrate the SDK using `@hackler/javascript-sdk`.

If you are using `@hackler/hackle-sdk`, you need to migrate to `@hackler/javascript-sdk`.
{% endhint %}

## Add SDK Dependency

[![](https://img.shields.io/npm/v/%40hackler%2Fjavascript-sdk)](https://www.npmjs.com/package/@hackler/javascript-sdk)

{% tabs %}
{% tab title="npm" %}

```shell
npm install --save @hackler/javascript-sdk
```

{% endtab %}

{% tab title="yarn" %}

```shell
yarn add @hackler/javascript-sdk
```

{% endtab %}
{% endtabs %}

## SDK Initialization

`hackleClient` is the class that provides methods for using SDK features.

To use the SDK, you need to initialize `hackleClient`.

#### Instantiation

Instantiate `hackleClient` by passing the SDK Key.\
`hackleClient` periodically synchronizes with the Hackle server as a background task to obtain the necessary information.

* You can find the SDK Key in [SDK Integration Info](https://dashboard.hackle.io/config/sdk-setting) located inside the Hackle Service Dashboard.

```javascript
const Hackle = require("@hackler/javascript-sdk");

// YOUR_SERVER_SDK_KEY 자리에 SDK 키를 넣습니다.
const hackleClient = Hackle.createInstance("YOUR_SERVER_SDK_KEY");
```

#### Initialization Complete

When the SDK is initialized, it fetches the necessary information from the Hackle server.

Initialization is performed asynchronously and you can receive the initialization completion callback via `onReady`.

{% hint style="warning" %}
If a user request arrives before the SDK is ready, **data may be lost.**
{% endhint %}

```javascript
hackleClient.onReady(() => {
  // SDK ready to use
  http.createServer((req, res) => {

  }).listen(3000)
});
```

## Shutdown

You must call the `close()` method when the application shuts down. This releases resources in use and sends any remaining events.

{% hint style="danger" %}
If the application shuts down without calling `close()`, **events may be lost.**
{% endhint %}

```javascript
process.on('SIGINT', function() {
  // kill signal
  hackleClient.close();
});
```


---

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