Detect output format from Vite config, not importer format#3
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Changes module format detection from importer-based (was it ESM or CJS?) to output-based (what format is Vite building for?). This fixes the bug where CJS files importing native modules in an ESM build output cause "Cannot determine intended module format" errors. Also adds comprehensive test coverage and documentation about multi-format build limitations. 🤖 Generated with Claude Code Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
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Summary
Fix module format detection to use Vite output format instead of importer format. This prevents "Cannot determine intended module format" errors when CommonJS files import native modules in ESM builds.
Changes
rollupOptions.output.formatorlib.formatsin Vite configsyntheticNamedExportstotrue(equivalent to previous change)Test Coverage
All 162 tests pass, including new integration tests for multi-format builds.
🤖 Generated with Claude Code