microsoft/monaco-editor · error · Error

Invalid argument

Error message

Invalid argument

What it means

Thrown by the monaco-editor (wrapper) release CI script when its CLI argument is neither 'stable' nor 'nightly'. Identical guard to the core script but for the consumer-facing monaco-editor package: 'stable' uses package.json's version directly, 'nightly' computes a prerelease version via getNightlyVersion and reads PRERELEASE_VERSION from env. Any other argv[2] value aborts before modifying package.json or running the build/test/package/smoketest pipeline.

Source

Thrown at scripts/ci/build-monaco-editor-pkg.ts:32

);

async function prepareMonacoEditorReleaseStableOrNightly() {
	const monacoEditorPackageJson = JSON.parse(
		await readFile(monacoEditorPackageJsonPath, { encoding: 'utf-8' })
	) as PackageJson;

	let version: string;

	const arg = process.argv[2];
	if (arg === 'stable') {
		version = monacoEditorPackageJson.version;
	} else if (arg === 'nightly') {
		version = getNightlyVersion(
			monacoEditorPackageJson.version,
			getNightlyEnv().PRERELEASE_VERSION
		);
	} else {
		throw new Error('Invalid argument');
	}

	await prepareMonacoEditorRelease(version);

	// npm package is now in ./out/monaco-editor, ready to be published
}

async function prepareMonacoEditorRelease(monacoEditorCoreVersion: string) {
	await group('npm ci', async () => {
		await run('npm ci', { cwd: resolve(rootPath, 'webpack-plugin') });
	});

	await group('Set Version & Update monaco-editor-core Version', async () => {
		const packageJson = JSON.parse(await readFile(monacoEditorPackageJsonPath, { encoding: 'utf-8' })) as PackageJson;
		packageJson.version = monacoEditorCoreVersion;
		packageJson.devDependencies['monaco-editor-core'] = monacoEditorCoreVersion;
		await writeJsonFile(monacoEditorPackageJsonPath, packageJson);
	});

View on GitHub (pinned to ca1b42dc89)

Solutions

1. Run with exactly one positional argument: `node scripts/ci/build-monaco-editor-pkg.ts stable` or `... nightly`.
2. When using npm run, pass the channel after `--`: `npm run build-monaco-editor-pkg -- nightly`.
3. In CI, validate the channel variable is non-empty and one of the two allowed values before invoking the script.
4. Check for casing/whitespace — the check is strict equality on lowercase strings.

Example fix

// before
$ node scripts/ci/build-monaco-editor-pkg.ts
// after
$ node scripts/ci/build-monaco-editor-pkg.ts nightly

const arg = process.argv[2];
if (arg !== 'stable' && arg !== 'nightly') {
  console.error('Usage: node scripts/ci/build-monaco-editor-pkg.ts <stable|nightly>');
  process.exit(2);
}
// proceed

function isReleaseChannel(arg: string | undefined): arg is 'stable' | 'nightly' {
  return arg === 'stable' || arg === 'nightly';
}

When it happens

Trigger: Running `node scripts/ci/build-monaco-editor-pkg.ts` without an argument or with a value other than 'stable'/'nightly'; a CI workflow that conditionally sets the channel and the condition evaluated to undefined; invoking through a runner that drops positional args.

Common situations: Developer testing the packaging flow locally; CI matrix variable not propagated; typo in the channel name; refactoring npm scripts and losing the `-- stable`/`-- nightly` suffix.

Related errors

• Invalid argument
• Cannot merge ${fieldName}: property '${key}' already exists
• Missing PRERELEASE_VERSION in process.env
• Missing VSCODE_REF in process.env

AI-assisted analysis of microsoft/monaco-editor@ca1b42dc89 (2026-08-13). Data as JSON: /api/errors/85b4b7a2ae0671f0. Report an issue: GitHub.