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Fix CJS build to actually emit CommonJS #4083

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Merged
DmitrySharabin merged 2 commits into from
Jun 2, 2026
+33 −2
Merged

Fix CJS build to actually emit CommonJS #4083

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c60204a
Fix CJS build to actually emit CommonJS
DmitrySharabin Jun 2, 2026
033ac24
Make CJS exports idiomatic so require() works without .default
DmitrySharabin Jun 2, 2026
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35 changes: 33 additions & 2 deletions scripts/build.js
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Original file line number Diff line number Diff line change
Expand Up @@ -250,7 +250,7 @@
renderChunk (code) {
const str = new MagicString(code);
str.replace(
/\/((?:[^\n\r[\\\/]|\\.|\[(?:[^\n\r\\\]]|\\.)*\])+)\/\s*\.\s*source\b/g,

Check warning on line 253 in scripts/build.js

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Unnecessary escape character: \/
(m, /** @type {string} */ source) => {
// escape backslashes
source = source.replace(
Expand Down Expand Up @@ -297,13 +297,32 @@
renderChunk (code) {
const str = new MagicString(code);
str.replace(
/^(?<indent>[ \t]+)grammar: (\{[\s\S]*?^\k<indent>\})/m,

Check warning on line 300 in scripts/build.js

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GitHub Actions / lint 

The quantifier '[\s\S]*?' is always entered despite having a minimum of 0. This is because the assertion '^' contradicts with the element(s) after the quantifier. Either set the minimum to 1 (+?) or change the assertion
(m, _, /** @type {string} */ grammar) => `\tgrammar: () => (${grammar})`
);
return toRenderedChunk(str);
},
};

/**
* Makes `require("prismjs")` return the default export directly with named
* exports as properties, so CJS consumers don't need `.default`.
*
* @type {Plugin}
*/
const cjsExportPlugin = {
name: 'cjs-default-export',
renderChunk (code) {
if (!code.includes('exports.default=')) {
return null;
}

code += 'module.exports=Object.assign(exports.default,exports);';

return { code, map: null };
},
};

/**
* @param {MagicString} s
* @returns {{ code: string; map: SourceMapInput }}
Expand Down Expand Up @@ -411,16 +430,20 @@
const bundles = {
esm: {
rollupOptions: defaultRollupOptions,
outputOptions: defaultOutputOptions,
outputOptions: {
...defaultOutputOptions,
format: 'es',
},
},
cjs: {
rollupOptions: {
...defaultRollupOptions,
plugins: [...defaultRollupOptions.plugins, commonjs()],
plugins: [...defaultRollupOptions.plugins, commonjs(), cjsExportPlugin],
},
outputOptions: {
...defaultOutputOptions,
dir: './dist/cjs',
format: 'cjs',
},
},
};
Expand All @@ -430,6 +453,14 @@
bundle.build = await rollup(bundle.rollupOptions);
await bundle.build.write(bundle.outputOptions);
}
// The root package.json has "type": "module", so Node treats all .js files as ESM.
// This overrides that for the CJS directory, since Node uses the nearest parent
// package.json to determine the module system: https://nodejs.org/api/packages.html#type
await writeFile(
path.join(DIST_DIR, 'cjs', 'package.json'),
JSON.stringify({ type: 'commonjs' }),
'utf-8'
);
}
finally {
for (const bundle of Object.values(bundles)) {
Expand Down
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