# 2. A module bundler - the fun begins

<figure><img src="https://1213438767-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F4DXEoZIzUdpt18CW2qTD%2Fuploads%2FzXjtfpnPjXaN7gAZDm9L%2Fexilewatch.webp?alt=media&#x26;token=74fc8000-b114-47be-bc13-cda9b75cd22f" alt="" width="256"><figcaption><p>exile.watch logo</p></figcaption></figure>

*This page is part of* [#the-toolkit-i-needed-to-make-it-all-happen](https://engineering.exile.watch/march-2024/lerna-the-hidden-powerhouse-of-exile.watch/..#the-toolkit-i-needed-to-make-it-all-happen "mention") *list - 2/7*

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{% hint style="info" %}
While you technically don't need a module bundler to get your project off the ground (you could just transpile each file from source to output directory and adjust your `package.json` accordingly), using one can streamline your process significantly.
{% endhint %}

I went with [Rollup](https://rollupjs.org/), thanks to my previous experience with it. You can read more about bundlers [here](https://snipcart.com/blog/javascript-module-bundler).

{% hint style="info" %}
*To keep it clear: Rollup itself is **not** opinionated - just look at this* [*list*](https://rollupjs.org/configuration-options/)
{% endhint %}

You can make Rollup's config somewhat opinionated easily which means that if you find a setup that works for one package, it's likely to work across the board with minimal fuss.

This consistency is a big win when managing multiple packages, ensuring they're all bundled efficiently in the same manner.

So, what's the deal with the packages in [exile.watch](https://exile.watch/)?

Each package serves its unique purpose, acting as a piece of the larger puzzle. They're essentially [boilerplates](https://en.wikipedia.org/wiki/Boilerplate_code) for different areas of functionality:

* [`@exile-watch/typescript-config`](https://github.com/exile-watch/splinters/pkgs/npm/typescript-config) bundles [TypeScript](https://www.typescriptlang.org/) and related dependencies. Adding it as a dev dependency means you’re indirectly installing TypeScript itself.
* [`@exile-watch/unit-testing-config`](https://github.com/exile-watch/splinters/pkgs/npm/unit-testing-config) includes everything you need for [React](https://react.dev/)/JavaScript unit testing, like [Vitest](https://vitest.dev/) and [@testing-library/react](https://testing-library.com/docs/react-testing-library/intro/), along with a few other relevant plugins.

And it doesn’t stop there.

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Each package adopts a specific stance, making sure that whether I’m whipping up a new consumer app, a browser extension, or even a desktop application, the development experience remains consistent.&#x20;

***Everything is expected to work, act, and behave the same, regardless of where it’s implemented.***

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*Having established our bundling strategy with Rollup, the next logical step is to consider where our packages will live.*&#x20;