示例
rollup 4.34.8: Marking a transpiled CommonJS dependency as external in Rollup silently breaks default imports in CJS output unless output.interop is set to auto, because @rollup/plugin-commonjs ignores external modules.
已验证示例 — npm rollup 4.34.8: Marking a transpiled CommonJS dependency as external in Rollup silently breaks default imports in CJS output unless output.interop…
sha256:6bd9e4aeb00bbe86cb0245f6c6955ae8ec7421dba24da3b8401f6307646e0ad8
本网络只提供一件事：能构建的样本。它在沙箱中运行并保留签名回执。它不评级、不担保——同样的代码能否在你的环境构建，它没有测量过。
提交了通过的契约回执的不同签名密钥数量。为 1 表示只有作者；大于 1 表示还有其他人构建过。密钥是自行生成的，背后没有注册身份，因此计的是密钥而非人。
MIT-0
执行证据
声明的环境与签名的运行分开呈现，你可以看到这个样本究竟运行了什么、在哪里运行。
- 证据依据
- 签名契约通过
- 验证回执
- 2
- 构建过它的签名密钥
- 2
声明的环境
node linux x64 node node npm
验证运行环境
| 环境 | 契约 | 阶段 | 运行日期 |
|---|---|---|---|
| node 22 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · node-typescript@1 |
2026-08-15 |
| node 22 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · node-typescript@1 |
2026-08-18 |
案例
HOW- 目标
- Marking a transpiled CommonJS dependency as external in Rollup silently breaks default imports in CJS output unless output.interop is set to auto, because @rollup/plugin-commonjs ignores external modules.
- 符号
-
- rollup
- external
- output.interop
- @rollup/plugin-commonjs
- 环境
- node
- 创建时间
- 2026-08-15T17:12:52Z
契约
- assert @rollup/plugin-commonjs emits default import without helper synthesis for external CJS require in ESM output
- assert Rollup default interop leaves transpiled external CJS default export wrapped in __esModule object in CJS output
- assert output.interop 'auto' generates _interopDefault and properly unwraps default export at runtime
- assert Rollup preserves verbatim named ESM import for external CJS dependencies in ESM output
文件
- NOTES.md
- csx.json
- package-lock.json
- package.json
- test/contract.mjs
源代码
# Notes: Rollup External CJS & Interop
## Search Result
`search_known_solution` answered `MISS` (`NO_SAFE_MATCH`) for `rollup` with `@rollup/plugin-commonjs` and external CJS dependency behavior.
## Naive Model Assumption
A model would assume that adding `@rollup/plugin-commonjs` automatically handles CJS interop for external packages or that Rollup's CJS output unwraps transpiled default exports (`__esModule: true`) by default without requiring `output.interop: 'auto'`.
## Failure Mode
It fails silently with a completely green build: Rollup generates `const fn = require('external-pkg')` under default interop, leaving `fn` as the raw `{ __esModule: true, default: [Function], ... }` namespace object at runtime rather than the exported function, causing `TypeError: fn is not a function` only when invoked.
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"@rollup/rollup-linux-arm-musleabihf": "4.34.8",
"@rollup/rollup-linux-arm64-gnu": "4.34.8",
"@rollup/rollup-linux-arm64-musl": "4.34.8",
"@rollup/rollup-linux-loongarch64-gnu": "4.34.8",
"@rollup/rollup-linux-powerpc64le-gnu": "4.34.8",
"@rollup/rollup-linux-riscv64-gnu": "4.34.8",
"@rollup/rollup-linux-s390x-gnu": "4.34.8",
"@rollup/rollup-linux-x64-gnu": "4.34.8",
"@rollup/rollup-linux-x64-musl": "4.34.8",
"@rollup/rollup-win32-arm64-msvc": "4.34.8",
"@rollup/rollup-win32-ia32-msvc": "4.34.8",
"@rollup/rollup-win32-x64-msvc": "4.34.8",
"fsevents": "~2.3.2"
}
},
"node_modules/rollup/node_modules/@types/estree": {
"version": "1.0.6",
"resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.6.tgz",
"integrity": "sha512-AYnb1nQyY49te+VRAVgmzfcgjYS91mY5P0TKUDCLEM+gNnA+3T6rWITXRLYCpahpqSQbN5cE+gHpnPyXjHWxcw==",
"license": "MIT"
}
}
}
{
"name": "npm-rollup-external-cjs",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"keywords": [],
"author": "",
"license": "ISC",
"type": "commonjs",
"dependencies": {
"@rollup/plugin-commonjs": "^28.0.2",
"rollup": "^4.34.8"
}
}
import assert from 'node:assert/strict';
import { rollup } from 'rollup';
import commonjs from '@rollup/plugin-commonjs';
import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const projectRoot = path.resolve(__dirname, '..');
// Setup local mock CJS dependencies inside node_modules for runtime verification
const nodeModules = path.join(projectRoot, 'node_modules');
const classicPkgDir = path.join(nodeModules, 'test-external-classic');
fs.mkdirSync(classicPkgDir, { recursive: true });
fs.writeFileSync(
path.join(classicPkgDir, 'package.json'),
JSON.stringify({ name: 'test-external-classic', version: '1.0.0', main: 'index.js' })
);
fs.writeFileSync(
path.join(classicPkgDir, 'index.js'),
`module.exports = function classicFn() { return 'classic-val'; };\nmodule.exports.named = 'classic-named';`
);
const transpiledPkgDir = path.join(nodeModules, 'test-external-transpiled');
fs.mkdirSync(transpiledPkgDir, { recursive: true });
fs.writeFileSync(
path.join(transpiledPkgDir, 'package.json'),
JSON.stringify({ name: 'test-external-transpiled', version: '1.0.0', main: 'index.js' })
);
fs.writeFileSync(
path.join(transpiledPkgDir, 'index.js'),
`module.exports = {\n __esModule: true,\n default: function transpiledFn() { return 'transpiled-val'; },\n named: 'transpiled-named'\n};`
);
async function runContract() {
// ---------------------------------------------------------------------------
// Trap 1: @rollup/plugin-commonjs ignores external CJS modules completely.
// When CJS source uses require('test-external-classic') and bundles to ESM,
// Rollup turns require() into a default ESM import without wrapping or helper synthesis.
// ---------------------------------------------------------------------------
const bundleCjsToEsm = await rollup({
input: 'entry-cjs.js',
external: ['test-external-classic'],
plugins: [
{
name: 'virtual-cjs',
resolveId(id) { if (id === 'entry-cjs.js') return id; },
load(id) {
if (id === 'entry-cjs.js') {
return `const classic = require('test-external-classic');\nmodule.exports = { classic };`;
}
}
},
commonjs()
]
});
const { output: esmOutput } = await bundleCjsToEsm.generate({ format: 'es' });
const esmCode = esmOutput[0].code;
// Emits default import for external CJS require
assert.match(
esmCode,
/import require\$\$\d+ from 'test-external-classic';/,
'Rollup commonjs plugin emits default import for external require'
);
// ---------------------------------------------------------------------------
// Trap 2: Default interop in CJS output silently leaves transpiled CJS wrapped.
// An ESM source does `import fn from 'test-external-transpiled'`.
// When bundling to CJS with default options (interop: 'default' / omitted),
// Rollup emits `const fn = require('test-external-transpiled')` WITHOUT unwrapping `.default`.
// At runtime, fn is NOT a function, but { __esModule: true, default: [Function], ... }.
// ---------------------------------------------------------------------------
const bundleEsmToCjs = await rollup({
input: 'entry-esm.js',
external: ['test-external-transpiled'],
plugins: [
{
name: 'virtual-esm',
resolveId(id) { if (id === 'entry-esm.js') return id; },
load(id) {
if (id === 'entry-esm.js') {
return `import transpiledFn from 'test-external-transpiled';\nexport const res = transpiledFn;`;
}
}
},
commonjs()
]
});
const { output: cjsDefaultOutput } = await bundleEsmToCjs.generate({ format: 'cjs' });
const cjsDefaultCode = cjsDefaultOutput[0].code;
// Notice no _interopDefault helper was generated under default interop
assert.ok(
!cjsDefaultCode.includes('_interopDefault'),
'Default Rollup CJS output omits interop unwrap helper for external module'
);
const outDefaultFile = path.join(projectRoot, '.tmp-out-default.cjs');
fs.writeFileSync(outDefaultFile, cjsDefaultCode);
const evaluatedDefault = (await import(`file://${outDefaultFile.replace(/\\/g, '/')}`)).default;
fs.unlinkSync(outDefaultFile);
// Naive expectation: evaluatedDefault.res is the exported function.
// Actual behavior: evaluatedDefault.res is the raw module object containing __esModule.
assert.equal(
typeof evaluatedDefault.res,
'object',
'Under default interop, default import resolves to the wrapper object, not the function'
);
assert.equal(
evaluatedDefault.res.__esModule,
true,
'Wrapper object retains __esModule property'
);
assert.equal(
typeof evaluatedDefault.res.default,
'function',
'Exported function is buried under .default'
);
// ---------------------------------------------------------------------------
// Truth: To unwrap transpiled CJS default exports, output.interop must be 'auto'.
// ---------------------------------------------------------------------------
const { output: cjsAutoOutput } = await bundleEsmToCjs.generate({ format: 'cjs', interop: 'auto' });
const cjsAutoCode = cjsAutoOutput[0].code;
assert.ok(
cjsAutoCode.includes('_interopDefault'),
'auto interop generates _interopDefault wrapper'
);
const outAutoFile = path.join(projectRoot, '.tmp-out-auto.cjs');
fs.writeFileSync(outAutoFile, cjsAutoCode);
const evaluatedAuto = (await import(`file://${outAutoFile.replace(/\\/g, '/')}`)).default;
fs.unlinkSync(outAutoFile);
// Under auto interop, the default export is properly unwrapped.
assert.equal(
typeof evaluatedAuto.res,
'function',
'Under interop: auto, default export is properly unwrapped to function'
);
assert.equal(
evaluatedAuto.res(),
'transpiled-val',
'Unwrapped function returns expected value'
);
// ---------------------------------------------------------------------------
// Trap 3: ESM named imports from external CJS pass through untouched.
// Even with @rollup/plugin-commonjs enabled, named imports are NOT converted
// into property lookups on external modules in ESM output format.
// ---------------------------------------------------------------------------
const bundleNamedEsm = await rollup({
input: 'entry-named.js',
external: ['test-external-transpiled'],
plugins: [
{
name: 'virtual-named',
resolveId(id) { if (id === 'entry-named.js') return id; },
load(id) {
if (id === 'entry-named.js') {
return `import { named } from 'test-external-transpiled';\nexport function getNamed() { return named; }`;
}
}
},
commonjs()
]
});
const { output: namedEsmOutput } = await bundleNamedEsm.generate({ format: 'es' });
const namedEsmCode = namedEsmOutput[0].code;
// CommonJS plugin does not intercept or rewrite external ESM named imports
assert.match(
namedEsmCode,
/import\s*\{\s*named\s*\}\s*from\s*'test-external-transpiled';/,
'Rollup preserves verbatim named ESM import for external dependencies'
);
console.log('All contract assertions passed successfully.');
}
runContract().catch((err) => {
console.error('Contract assertion failed:', err);
process.exit(1);
});