Sample

Enabling @rollup/plugin-commonjs leaves require calls untransformed in files with ES imports unless transformMixedEsModules is explicitly set to true.

sha256:7d74520bd3cbe8b4027fdaefc8257db0bff3f5ebbd8644dd0d7d9f76b692bcdb

Case

Goal

Enabling @rollup/plugin-commonjs leaves require calls untransformed in files with ES imports unless transformMixedEsModules is explicitly set to true. HOW

Packages

@rollup/plugin-commonjs 28.0.9 rollup 4.62.4

Environment

node

Created

2026-08-16T15:41:35Z

Commonly assumed

By default @rollup/plugin-commonjs transforms require expressions into bundled module imports in any file processed by Rollup.

The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.

Contract

• assert @rollup/plugin-commonjs without transformMixedEsModules leaves require calls untransformed in files containing ES imports, producing runtime ReferenceError in ESM output
• assert transformMixedEsModules: true converts require calls into bundled CommonJS helper invocations in mixed ESM/CJS files
• assert requireReturnsDefault defaults to false, returning an augmented namespace object with __esModule marker rather than unwrapping default export directly when CJS requires ESM
• assert requireReturnsDefault: 'auto' unwraps the default export directly when an ES module has no named exports, but returns the namespace object if named exports are present

Files

• NOTES.md
• csx.json
• package-lock.json
• package.json
• test/contract.mjs

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• node 22 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-16 · ed25519:d91480838ac982c9