PrismJS's CJS global state is fundamentally incompatible with Vite's ESM
dev mode, causing missing language support (~40% of dropdown languages)
and fragile loading hacks (optimizeDeps, global assignment).
Replace the entire Prism integration with highlight.js/lib/common which
is ESM-native, has no global state, and covers all 22 dropdown languages
out of the box (~37 common languages included).
Implementation:
- Custom CodeHighlightPlugin using hljs.highlight() for tokenization
- HTML parser extracts flat tokens from hljs output (handles nested spans)
- Token type mapping from hljs scopes to Lexical codeHighlight theme keys
- Selection preservation via absolute character offset save/restore
- Re-entrancy guard prevents infinite transform loops
- Removed @lexical/code-prism import and Vite optimizeDeps workaround
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Remove the prismSetup module that imported prismjs directly — it
caused Vite to pre-bundle prismjs into a separate chunk from
@lexical/code-prism, breaking the CJS require chain. Language
components tried to call Prism.languages.extend() before the base
grammars were available, crashing the app.
Instead, add optimizeDeps.include for prismjs and @lexical/code-prism
so Vite pre-bundles them together, preserving the correct CJS
evaluation order within a single chunk.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
