[lexical-playground] Feature: Add PagesExtension

[ibastawisi]

Description

This pull request introduces a comprehensive "Pages" feature to the Lexical Playground, adding support for document pagination, page setup, and print-friendly styling. The main changes include new node types for representing pages and their content, a page setup node for configuring size and margins, and significant CSS updates for print output and UI enhancements.

Pages feature and node architecture:

• Added new node types: PageNode, PageContentNode, and PageSetupNode, along with supporting types and constants, to represent document pages, their content, and page setup (size, orientation, margins). These nodes manage pagination logic, page measurement, overflow/underflow handling, and serialization. [1] [2] [3] [4] [5] [6]
• Integrated the PagesExtension into the main playground app, enabling the new pages functionality in the editor. [1] [2]

Print and UI enhancements:

• Added print-specific CSS rules to ensure correct page rendering, hide non-editor elements, and optimize color and layout for printing. [1] [2]
• Updated editor and dropdown styling, including new icons for page setup and improved submenu chevrons, and slightly increased the editor shell's maximum width. [1] [2] [3]

These changes lay the foundation for multi-page document editing and WYSIWYG print output in the Lexical Playground.

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Project	Deployment	Actions	Updated (UTC)
lexical	Ready	Preview, Comment	Apr 12, 2026 5:03am
lexical-playground	Ready	Preview, Comment	Apr 12, 2026 5:03am

[etrepum]

This is probably one of the most requested features and generally the trickiest to build! I haven't had time to do a close inspection yet, but here are some general notes on the architecture. Basically it could be made a lot less react-dependent (everything but the dropdown UI itself I think) and follow newer lexical conventions more closely to reduce boilerplate required for clone/serialization/etc.

[etrepum]

I think this looks great, of course the one thing missing here would be adding some e2e tests to show that it works as expected but I think it's also early enough and isolated enough from other playground functionality that we could do that later (e.g. after implementing better TextNode splitting)

[ibastawisi]

I'm having a hard time getting text splitting to work as expected, I will try a different approach later today but things look harder than I thought.
If I couldn’t figure it out today, then we'd better open an issue and think about it in another day