Add defaultStyle to a TipTap text block

[VPS-Andreas]

The styling select always offered a "Default" entry standing for "no style", even where a design has no unstyled variant and every text block is meant to carry one of the configured styles. Editors had to pick the right style by hand on every new text block, and forgetting it produced unstyled content.

A text block (or list) with a defaultStyle has no such state:

createTipTapRichTextBlock({
    textBlocks: [
        { name: "heading-1", label: "Heading 1", tag: "h1", styles: headlineStyles, defaultStyle: "headline300" },
        { name: "heading-2", label: "Heading 2", tag: "h2", styles: headlineStyles, defaultStyle: "headline400" },
    ],
});

The select drops its "Default" entry, and the style is applied to new content and to every text block the editor creates without one — pressing Enter at the end of a text block, the Mod-Alt-<level> shortcuts, pasting. Rather than reimplementing each of those paths, a ProseMirror plugin fills in a missing style on document change, so opening older content leaves it untouched and does not mark the document as changed. Switching the type keeps a style the new text block also offers and falls back to its defaultStyle otherwise, and toggling a list hands the text block to the list's styles or back — through the toolbar buttons and Mod-Shift-7/Mod-Shift-8 alike.

Because the default sits on the text block rather than on a tag, two text blocks sharing a tag can have different defaults, and a text block without one keeps its "Default" entry next to text blocks that have one.

Third of four stacked pull requests, on top of #6383 and #6382; #6385 splits the block's Storybook stories by topic.

Example

createTipTapRichTextBlock.test.ts/.test.tsx cover the validation and the content a default style produces. The Storybook story Default Text Block Style walks through a text block with a default, one without, and the styled lists.

Session: https://claude.ai/code/session_f3c6ad37-c68b-4187-85b6-2abe5aa95c35

[VPS-Obi]

We'll review this once #6383 has been merged.

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Adds optional default styling to text blocks in the rich text editor.

The PR appears safe to merge based on the reviewed changes.

Summary

Adds configurable default styles for TipTap text blocks and lists, including editor-side style reconciliation and matching API validation.

• The follow-up changes reconcile styles per selected block and correct incompatible styles created by shortcuts and other editor actions.
• The previously reported findings are resolved or withdrawn; no new actionable issue was established.

_{Reviews (3) · Last reviewed commit: "cms-api: Pass the DraftJS list item's pa..."}

[VPS-Andreas]

@greptileai review

[VPS-Obi]

Will this clash with the text block's priority declared here? https://github.com/vivid-planet/dextinity/pull/6520/changes#diff-6adff581824fc49917cd599da9fa0e7a62c2242f5a3bc20bcd959ae4ece67024R38

[VPS-Andreas]

No — textBlockList is an Extension, not a Node, so it contributes nothing to the schema: TipTap builds the schema from splitExtensions(...).nodeExtensions, and this priority only orders plugins and shortcuts. With #6520 merged into this branch, the running editor reports defaultType: textBlock and a node order starting with textBlock.

The keys don't overlap either: textBlock takes Mod-Alt-<level>, textBlockList takes Mod-Shift-7/Mod-Shift-8. The 1100 only has to beat @tiptap/extension-list, which registers bulletList, orderedList and listKeymap without a priority of their own, so at the default 100.

[VPS-Obi]

@VPS-Andreas please test this change in Demo as well and verify that saving is possible to prevent issues such as described here: #6520. Unfortunately, we can't test this end to end in Storybook alone.

[VPS-Andreas]

Tested in Demo. defaultStyle had no example there, so the paragraph now has paragraph300 and both lists list300 — without that the run wouldn't touch the feature at all.

Saving works, and the content comes back unchanged after a reload. A paragraph gets its default filled in on the first edit and the styling select drops its "Default" entry; Mod-Shift-7 over two differently styled paragraphs gives each list item the list's default instead of collapsing them onto one style; Mod-Alt-1 drops a style the target text block doesn't offer; and switching the type inside a list lifts the block out and resolves the style for the text block it becomes, while the remaining item keeps the list's style.

Before #6520 was merged into this branch, saving did fail here: toggling a list at the end of the content left an empty bulletList behind, which the API rejected. With #6520 the trailing node is a text block again — and it gets the paragraph's default style — so saving goes through.