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fix: handle "main": false in package.json without crashing #210

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Merged
antfu merged 1 commit into from
Sep 16, 2026
Merged

fix: handle "main": false in package.json without crashing #210

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10 changes: 10 additions & 0 deletions packages/node-modules-tools/src/analyze-esm.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -26,4 +26,14 @@ describe('analyzePackageModuleType', () => {
exports: nestExports(11, './index.mjs'),
})).toBe('unknown')
})

it('handles main: false without crashing', () => {
// Some packages (e.g. math-intrinsics, dunder-proto) declare "main": false
// to indicate exports-only packages. Should not crash.
expect(analyze({
name: 'math-intrinsics',
main: false as any,
exports: { './abs': './abs.js' },
})).toBe('unknown')
})
})
13 changes: 8 additions & 5 deletions packages/node-modules-tools/src/analyze-esm.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -69,13 +69,16 @@ export function analyzePackageModuleType(pkgJson: PackageJson): PackageModuleTyp
if (pkgJson.name?.startsWith('@types/'))
return 'dts'

// Ensure main is a string (can be false in some packages)
const main = typeof pkgJson.main === 'string' ? pkgJson.main : undefined

// Native binary packages (e.g. @oxc-parser/binding-linux-x64-gnu)
if (pkgJson.main?.endsWith('.node'))
if (main?.endsWith('.node'))
return 'bin'

const hasExports = pkgJson.exports != null
const hasModule = !!pkgJson.module
const hasMain = !!pkgJson.main
const hasMain = !!main
const isTypeModule = pkgJson.type === 'module'

// Check exports field for module format indicators
Expand Down Expand Up @@ -103,15 +106,15 @@ export function analyzePackageModuleType(pkgJson: PackageJson): PackageModuleTyp

// Legacy detection (no exports or exports without clear conditions)
if (hasModule && hasMain) {
const mainIsCJS = pkgJson.main?.endsWith('.cjs')
|| (pkgJson.main?.endsWith('.js') && !isTypeModule)
const mainIsCJS = main?.endsWith('.cjs')
|| (main?.endsWith('.js') && !isTypeModule)
return mainIsCJS ? 'faux' : 'esm'
}

if (hasModule)
return 'faux'

if (isTypeModule || (hasMain && pkgJson.main?.endsWith('.mjs')))
if (isTypeModule || (hasMain && main?.endsWith('.mjs')))
return 'esm'

if (hasMain)
Expand Down
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