web: add default export to CJS bundle#5305
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amaanq merged 1 commit intotree-sitter:masterfrom Feb 10, 2026
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Why? ==== The CJS bundle sets __esModule: true and exports named members (Parser, Language, etc.) but has no .default property. When TypeScript consumers use module: "commonjs" + esModuleInterop: true, the __importDefault helper sees __esModule and returns module.default — which is undefined. This causes `import Parser from 'web-tree-sitter'` to silently resolve to undefined at runtime despite typechecking cleanly. Reproduction: https://github.com/chadxz/web-tree-sitter-default-export-type-issue How? ==== - Traced the issue by inspecting the CJS bundle output and confirming __esModule is set but no .default exists - Added `module.exports.default = module.exports;` via esbuild's footer option, conditionally for CJS builds only - Verified by patching the published 0.26.3 bundle in a repro project and confirming the default import resolves correctly - Built the full ESM + CJS bundles from source to confirm the footer appears in the CJS output and the .d.cts types align
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@WillLillis @clason is this something you'd be interested in merging? Any other validation you'd like to see? |
WillLillis
approved these changes
Feb 10, 2026
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Successfully created backport PR for |
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Thanks all! 🙌 |
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Why?
The CJS bundle sets __esModule: true and exports named members
(Parser, Language, etc.) but has no .default property. When
TypeScript consumers use module: "commonjs" + esModuleInterop:
true, the __importDefault helper sees __esModule and returns
module.default — which is undefined. This causes
import Parser from 'web-tree-sitter'to silently resolve toundefined at runtime despite typechecking cleanly.
Reproduction: https://github.com/chadxz/web-tree-sitter-default-export-type-issue
How?
confirming __esModule is set but no .default exists
module.exports.default = module.exports;viaesbuild's footer option, conditionally for CJS builds only
project and confirming the default import resolves correctly
footer appears in the CJS output and the .d.cts types align