Expose the minimal Interactivity API in a public package

[luisherranz]

• Part of Block API #41236.

This list of tasks is aimed at exposing publicly the minimal version of the Interactivity API that we are using privately for the Core blocks so people can start experimenting with it.

IMPORTANT

• We'll work on this in a separate interactivity branch.
• ⚠️ We won't merge any of this with trunk.
• We'll wait until the WP 6.3 feature freeze to merge it.

Next

• Add the runtime to its own package (@wordpress/interactivity)
• Build that package with Preact
  • We should use our custom Webpack config.
  • We probably don't need this for the view.js files.
• Expose the store as a global
  • We don't need to add the DependencyExtractionWebpackPlugin yet, we can do const { store } = wp.interactivity, but maybe it works out of the box (it worked out of the box).
• Delete the filter that adds defer to the scripts
  • We can add defer again later.
• Make the necessary changes to the blocks/behaviors, so they start using this version
  • Move the interactivity.js files to simple view.js files?
• Delete the private runtime

Once we finish this list of tasks, the interactivity branch will be ready to be merged with trunk and we can continue adding more features. But again, we'll wait until the 6.3 feature freeze to merge it.

[DAreRodz]

I'll start moving the runtime to @wordpress/interactivity. Once I have a PR, I'll continue with the following tasks in the same PR (if I feel it appropriate). 🧑‍💻

[DAreRodz]

This is the PR I've created (currently a draft).

• Create @wordpress/interactivity with the Interactivity API #50906

Development is progressing well, although I faced some issues I'd like to discuss. I posted a comment in the PR summarizing them.

[DAreRodz]

All tasks are currently finished on #50906. ✅

I think we still have to write a proper README file, but other than that, I don't see any pending work.

The PR is still a draft. As we don't want to merge it yet, I don't know if it would be better to wait to set it as ready for review.

[luisherranz]

Amazing work, David! 🎉

Closing this as finished, we'll keep working on the next steps on: #51056