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Recommended Project Structure

So far we have seen how to add Bento to your project. In this section let's expand on what is a recommend project structure for your app.

info

This section is merely a recommendation and it's an optional part of the documentation. It's useful if you're starting from scratch and you are wondering how to best organize your project.

Feel free to skip it if you already have a plan on how to structure the various modules of your application.

Overall organization​

When it comes to design system code, we recommend to split it from your application code.

note

We are going to use pnpm workspaces for these examples, but the structure with npm or yarn is almost identical.

Something like:

my-project/
├─ packages/
│  ├─ design-system/
│  ├─ app/
├─ package.json
├─ pnpm-workspace.yaml/
tip

It's not mandatory to have the modules inside a packages directory, but we reckon it keeps things organized and it allows the use of wildcards for identifying workspace projects, which is convenient whenever you need to add or remove one:

my-project/pnpm-workspace.yaml
packages:
  - "packages/**"

The reason for splitting the design system code from the application code is that it clearly separates the concerns:

  • the design-system module should be focused on UI components and utilities
  • the app code should be focused on the business logic and it will use the UI components

Having them as separate workspace projects is a good practice since it allows setting up different dependencies for each of them.

For example, we recommend not adding a i18n library (like react-intl or react-i18next) to the design-system project, so you will automatically make sure the UI components are parametric with respect to the localization aspects.

Another example is not setting up a styling library (like Vanilla Extract) in app: ideally, app should only use the design system components and in those rare cases in which this isn't true, plain CSS support (as it comes with tools like Create React App) should be enough. If you find yourself needing a lot of custom styling in app, then it's a good indication that something is wrong with your design system.

The design-system module​

The design-system module is a dependency of the app module. We recommend to treat this module as if it were a completely separate library that will be distributed on npm. Even if app will consume this module locally, this creates a more effective separation and it will ease the process of actually publishing the design system library in case you need to in the future.

With that in mind, let's see how to set up the design-system module.

Setting up Vanilla Extract​

As we've discussed already, Vanilla Extract is the library Bento uses for styling. It's not strictly necessary for you to use Bento, but it makes things easier for a few reasons:

  • it allows you to define Bento themes for you project in a type-safe way (see Theming)
  • it allows you to extend Bento design tokens, again in a type-safe way (see Atoms augmentation)
  • it's in general a CSS library which is very suitable for writing UI components, thanks for to its powerful API (see for example the Recipes API)

Since we want this module to be (potentially) distributed on npm, we want to bundle our code, including CSS files.

Vanilla Extract supports several popular bundlers, but for a design system package we recommend using tsup, which is based on esbuild and is especially well-suited for TypeScript libraries.

Here's a setup you can use to get started:

pnpm add -D tsup @vanilla-extract/esbuild-plugin

Create a file named tsup.config.ts in your project root:

import { defineConfig } from "tsup";
import { vanillaExtractPlugin } from "@vanilla-extract/esbuild-plugin";

export default defineConfig({
  entry: ["src/index.ts"],
  outDir: "lib",
  esbuildPlugins: [vanillaExtractPlugin()],
  dts: true,
  // Include here the css files coming from external dependencies, which we
  // recommend to bundle in your design system package.
  noExternal: [
    "@buildo/bento-design-system/index.css",
    // e.g. here's how to include fonts from Fontsource, a popular library for self-hosting fonts
    // "@fontsource",

    // Uncomment the next line if you want to bundle all css files coming from external dependencies
    // NOTE: this may significantly slow down your build, depending on your setup.
    // /\.css$/,
  ],
});

And a file named jsxShim.ts in your project root:

// See https://esbuild.github.io/content-types/#auto-import-for-jsx
import * as React from "react";
export { React };

Done! Now you can add two scripts to your package.json:

my-project/packages/design-system/package.json
"scripts": {
  "build": "tsup --minify --clean",
  "start": "tsup --watch",
}

The final layout will look like:

my-project/
├─ packages/
│  ├─ design-system/
│  │  ├─ src/
│  │  │  ├─ index.ts
│  │  ├─ package.json
│  │  ├─ tsup.config.ts
│  │  ├─ jsxShim.ts
│  ├─ app/
├─ package.json
├─ pnpm-workspaces.yaml

packages/design-system/src/index.ts is where you configure and export Bento components.

Your index.ts will look something like this:

my-project/packages/design-system/src/index.ts
import { createBentoProvider } from "@buildo/bento-design-system";

// Export the Bento components you want to use in your app
export { Button, Card, Title /*...*/ } from "@buildo/bento-design-system";

// Export any other custom component
export * from "./components/MyCustomComponent/MyCustomComponent";

// You can use the createBentoProvider facility to create a BentoProvider with
// your custom config, theme and sprinkles (see the section about Customization to learn about these)
export const BentoProvider = createBentoProvider(config, theme, sprinkles);

, like we saw in Quick Start.

Setting up Turborepo​

Turborepo is a build tool for monorepos, which eases the job of building and running packages inside your monorepo.

It's completely optional and not required at all to work in the setup we've described so far, but it makes it a bit more practical to use and it helps a lot when your monorepo complexity grows to include more modules and scripts to run.

You can install and setup Turborepo by following the official documentation.

Here is a pipeline which works well in the setup we've seen so far:

my-project/turbo.json
{
  "$schema": "https://turborepo.org/schema.json",
  "baseBranch": "origin/main",
  "pipeline": {
    "start": {},
    "build": {
      "dependsOn": ["^build"]
    }
  }
}

Finally, add some scripts to run Turborepo in your top-level package.json:

my-project/package.json
"scripts": {
  "start": "turbo run start",
  "build": "turbo run build"
}

This will ensure that when you run start, both your app and the design system will start in watch mode, so that any changes to the design system will be propagated to the app. Also, when you run build, the app will be built only after the design-system is built instead.

This is a very basic setup, but Turborepo gives you a very straightforward way to express it and you already benefit from local caching (e.g. the design system won't be rebuilt if you only changed the app since your last build). Also, you are in a good position to accomodate more complex setups, if needed.