Fix: Whitespace characters will incorrectly trigger foster parenting.

[zimya]

Initial checklist

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• I made sure the docs are up to date
• I included tests (or that’s not needed)

Description of changes

Fixes #30

This PR fixes an issue where structural whitespace (like newlines) inside table elements gets incorrectly foster-parented outside the table when passing a hast tree through rehype-raw.

Currently, hast-util-raw unconditionally maps all text nodes to Token.TokenType.CHARACTER when feeding tokens to parse5. When parse5 receives a CHARACTER token inside restricted table modes (e.g., in table body, in row), it treats it as illegal text and triggers HTML5 Foster Parenting, extracting the newlines and flattening the table.

This PR added a regex check (/^[ \t\n\f\r]+$/) in the text() handler. If the text node contains only HTML whitespace characters, it is correctly mapped to Token.TokenType.WHITESPACE_CHARACTER. This allows parse5 to safely ignore/append the formatting whitespace without breaking the table structure.

[github-actions]

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[ChristianMurphy]

Could you add a test for this?

[Copilot]

Pull request overview

This PR addresses incorrect HTML5 foster parenting triggered by structural whitespace within table-related insertion modes when feeding tokens into parse5, improving table structure preservation when running a HAST tree through hast-util-raw/rehype-raw.

Changes:

• Classify whitespace-only text nodes as Token.TokenType.WHITESPACE_CHARACTER instead of always CHARACTER.
• Make namespace detection in startTag() resilient when there is no current open element.
• Minor formatting/indentation adjustment in documentMode() (no functional change).

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[Copilot]

Please add a regression test for this new whitespace-token behavior (e.g., a <table> with \n / formatting-only text nodes between table elements) to ensure raw() no longer causes parse5 foster parenting to move those text nodes outside the table.

[Copilot]

The /^[ \t\n\f\r]+$/ regex literal is evaluated each time text() runs, creating a new RegExp object per text node. Consider hoisting it to module scope (or reusing a shared constant) to avoid unnecessary allocations in large documents.

[zimya]

Thank you for the review! I've hoisted the RegExp to the module scope as whitespaceExpression to avoid unnecessary allocations, and added a regression test checking that whitespace text nodes within tables are kept inside the table and not foster-parented.