Embrace the modularity

The WordPress block editor is based around the idea that you can combine independent blocks together to write your post or build your page. Blocks can also use and interact with each other. This makes it very modular and flexible.

But the Block Editor does not embrace modularity for its behavior and output only, it is also built from the ground up as several reusable and independent modules or packages, that, combined together lead to the application and interface we all now. These modules are known as WordPress packages and are published and updated regularly on the npm package repository.

Right now these packages are built in the Block Editor Repository and used to power the block editor. Ultimately, these packages will be used to power any page in the WordPress Admin.

Modular architecture

Using a modular architecture has several benefits for all the actors involved:

  • Each package is an independent unit and has a well defined public API that is used to interact with other packages and third-party code. This makes it easier for Core Contributors to reason about the codebase. They can focus on a single package at a time, understand it and make updates while knowing exactly how these changes could impact all the other parts relying on the given package.
  • A module approach is also beneficial to the end-user. It allows to selectively load scripts on different WordPress Admin pages while keeping the bundle size contained. For instance, if we use the components package to power our plugin’s settings page, there’s no need to load the block-editor package on that page.
  • This architecture also allows third-party developers to reuse these packages inside and outside the WordPress context by using these packages as npm or WordPress script dependencies.

Types of packages

Almost everything in the Gutenberg repository is built into a package. We can split the packages into two different types:

Production packages

These are the packages that ship in WordPress itself as JavaScript scripts. These constitute the actual production code that runs on your browsers. As an example, there’s a components package serving as a reusable set of React components used to prototype and build interfaces quickly. There’s also an api-fetch package that can be used to call WordPress Rest APIs.

Third-party developers can use these production packages in two different ways:

  • If you’re building a JavaScript application, website, page that runs outside of the context of WordPress, you can consume these packages like any other JavaScript package in the npm registry.
npm install @wordpress/components
import { Button } from '@wordpress/components'; function MyApp() { return ( <Button>Nice looking button</Button> ); }
  • If you’re building a plugin that runs on WordPress, you’d probably prefer consuming the package that ships with WordPress itself. This allows multiple plugins to reuse the same packages and avoid code duplication. In WordPress, these packages are available as WordPress scripts with a handle following this format wp-package-name (e.g. wp-components). Once you add the script to your own WordPress plugin scripts dependencies, the package will be available on the wp global variable.
// myplugin.php // Exemple of script registration dependending on the "components" and "element packages. wp_register_script( 'myscript', 'pathtomyscript.js', array ('wp-components', "wp-element" ) );
// Using the package in your scripts const { Button } = wp.components; function MyApp() { return ( <Button>Nice looking button</Button> ); }

Script dependencies definition can be a tedious task for developers. Mistakes and oversight can happen easily. If you want to learn how you can automate this task. Check the @wordpress/scripts and @wordpress/dependency-extraction-webpack-plugin documentation.

Packages with stylesheets

Some production packages provide stylesheets to function properly.

  • If you’re using the package as an npm dependency, the stylesheets will be available on the build-style folder of the package. Make sure to load this style file on your application.
  • If you’re working in the context of WordPress, you’ll have to enqueue these stylesheets or add them to your stylesheets dependencies. The stylesheet handles are the same as the script handles.

In the context of existing WordPress pages, if you omit to define the scripts or styles dependencies properly, your plugin might still work properly if these scripts and styles are already loaded there by WordPress or by other plugins, but it’s highly recommended to define all your dependencies exhaustively if you want to avoid potential breakage in future versions.

Packages with data stores

Some WordPress production packages define data stores to handle their state. These stores can also be used by third-party plugins and themes to retrieve data and to manipulate it (Refer to my previous post on the subject for more details here). The name of these data stores is also normalized following this format core/package-name (E.g. the @wordpress/block-editor package defines and uses the core/block-editor package).

If you’re using one of these stores to access and manipulate WordPress data in your plugins, don’t forget to add the corresponding WordPress script to your own script dependencies for your plugin to work properly. (For instance, if you’re retrieving data from the core/block-editor store, you should add the wp-block-editor package to your script dependencies like shown above).

Development packages

These are packages used in development mode to help developers with daily tasks to develop, build and ship JavaScript applications, WordPress plugins and themes. They include tools for linting your codebase, building it, testing it…

Going further

The WordPress packages are a gold mine and a huge time saver when it comes to building JavaScript application whether as a WordPress plugin or an independent application.

In the next weeks, I’ll try to write a series of posts to explain some of these packages in detail, how to reuse them in your own code. In the meantime, I encourage you to explore the documentation of the different packages on the block editor handbook.

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