feat!: prevent FlatList item re-rendering - #1080
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- Introduce MarkdownBlock (id+token+raw) with content-hash keys via useMarkdownBlocks (src/hooks/useMarkdownBlocks.ts:10, src/lib/types.ts:17) replacing index keys (src/lib/Markdown.tsx:44) - Memoize block rows with React.memo and raw/type comparators (src/lib/MarkdownBlock.tsx:24) so only changed/new blocks re-parse - Refactor Markdown to data=MarkdownBlock[] with stable FlatList keyExtractor and ScrollView fallback when flatListProps=null (src/lib/Markdown.tsx:31,51) - Optimize useMarkdown with token-level reuse for append and per-index edits (src/hooks/useMarkdown.ts:84,125) - Stabilize ReactComponentTokenizer keys and add Renderer.resetKeys (src/hooks/useMarkdownWithComponents.tsx:39, src/lib/Renderer.tsx:13) - Update docs, exports and snapshots; fixes #451 BREAKING CHANGE: Markdown flatListProps generic is now FlatListProps<MarkdownBlock> | null; snapshots change; callers should memoize styles/theme/renderer objects to benefit from bail-out
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Fixes #451
Root cause
Markdown used data=ReactNode[] + index keys (src/lib/Markdown.tsx:30) causing every value change to recreate all identities and FlatList to re-render all rows. Unstable styles/renderer and global slugger counter amplified.
Changes
resetKeys() (src/lib/Renderer.tsx:13), useMarkdownWithComponents stable ids (src/hooks/useMarkdownWithComponents.tsx:39)
Verification
BREAKING CHANGE: flatListProps generic is FlatListProps|null; snapshots change; callers should memoize styles/theme/renderer.