* [App editor](build-apps/app-editor.md)

* [Event handlers](build-apps/event-handlers.md)

* [Write JavaScript](build-apps/write-javascript/README.md)

* [Version and release management](build-apps/version-and-release-management.md)

Every developer learns one of the most important principles of software engineering early in their career: DRY (Don’t Repeat Yourself). Using third-party libraries can save your time as you do not need to develop the functionality that the library provides. Openblocks provides some built-in third-party libraries for common uses, and you can manually import other libraries on demand.

Openblocks provides some JavaScript built-in libraries for use:

| numbro | [https://numbrojs.com/format.html](https://numbrojs.com/format.html) | 2.3.6 |

| papaparse | [https://www.papaparse.com/docs](https://www.papaparse.com/docs) | 5.3.2 |

Openblocks supports setting up preloaded JavaScript and libraries which can be **app-level** or **workspace-level**.

Now you can write code in **JS query** to test its usage with `cowsay.say`:

or in component **Properties**:

And since you have set up cowsay just for **Openblocks's new application 1,** you can not use cowsay in another app.

Navigate to **Workspace settings** > **Advanced** > **JavaScript library** > **Add a library**. Then paste the **cowsay** link here and click **Save**. Now you can use **cowsay** library **** in any app of your workspace.\