> For the complete documentation index, see [llms.txt](https://docs.hollaex.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hollaex.com/plugins/develop-plugins/advanced/plugin-libraries.md).

# Plugin Libraries

Libraries allow access to functionality for plugins. Some are included within the HollaEx Kit, but you have the ability to import ones of your own choosing that have not been included

There are three types of third-party libraries for all plugins: *preconfigured*, *default*, and *plugin specific*.

### Preconfigured Libraries

Preconfigured libraries are libraries that have the same configuration for all plugins. These are included in an object `this.pluginLibraries`. The libraries included are:

* [`app`](https://www.npmjs.com/package/express) - Express app (v4.16.2)
* [`toolsLib`](https://github.com/bitholla/hollaex-tools-lib) - HollaEx Tools Library
* [`loggerPlugin`](https://www.npmjs.com/package/winston) - Winston logger (v3.2.1)

### Default Libraries

Default libraries are libraries that are already installed in the Kit itself. These can be imported using `require`. Please take a look at the Kit [`package.json`](https://github.com/bitholla/hollaex-kit/blob/master/server/package.json) file for all default libraries included. Some are:

<details>

<summary>Click here to view the default libraries</summary>

* [`lodash`](https://www.npmjs.com/package/lodash) - (v4.17.20)
* [`expressValidator`](https://www.npmjs.com/package/express-validator) - (v6.7.0)
* [`multer`](https://www.npmjs.com/package/multer) - (v1.4.2)
* [`moment`](https://www.npmjs.com/package/moment) - (v2.21.0)
* [`mathjs`](https://www.npmjs.com/package/mathjs) - (v3.20.2)
* [`bluebird`](https://www.npmjs.com/package/bluebird) - (v3.5.3)
* [`rp`](https://www.npmjs.com/package/request-promise) - Request promise (v4.2.2)
* [`uuid`](https://www.npmjs.com/package/uuid) - (v3.2.1)
* [`umzug`](https://www.npmjs.com/package/umzug) - (v2.3.0)
* [`sequelize`](https://www.npmjs.com/package/sequelize) - (v4.37.7)
* [`json2csv`](https://www.npmjs.com/package/json2csv) - (v4.5.4)
* [`flat`](https://www.npmjs.com/package/flat) - (v5.0.0)
* [`cron` ](https://www.npmjs.com/package/node-cron) - (v2.8.5)
* [`bcryptjs`](https://www.npmjs.com/package/bcryptjs) - (v2.4.3)
* [`validator`](https://www.npmjs.com/package/validator) - (v9.4.1)
* [`cors`](https://www.npmjs.com/package/cors) - (v2.8.5)

</details>

### Plugin Specific Libraries

Plugin-specific libraries are libraries that are not installed in the Kit but are required for the plugin. These can be installed through the `prescript.install` object in the plugin `config.json file` and imported using `require`.&#x20;

{% hint style="danger" %}
**Do not add** any plugin-specific libraries that are already included by default.&#x20;

A different version could be installed which can cause unexpected bugs.
{% endhint %}

To add a plugin-specific library on installation, include the library name inside the `install` array in the  `prescript` object. To specify a version, include the `@` symbol with the version desired (similar to how a basic npm install works).

```javascript
{
    ...
    prescript: {
        install: ['hello-world-npm']
    },
    ...
```