babel/babel · error · ConfigError

Config file contains no configuration data

Error message

Config file contains no configuration data

What it means

loadConfig resolves a config by name (via require.resolve) and then reads it; if readConfig returns null (the file exists but contains no recognized config - e.g. an empty default export, or an extension that resolved to an empty parse), loadConfig throws 'Config file contains no configuration data'. This path is used when a config is explicitly referenced by name (e.g. BABEL_SHOW_CONFIG_FOR or programmatic configFile option pointing at a module).

Source

Thrown at packages/babel-core/src/config/files/configuration.ts:318

  }, previousConfig);

  if (config) {
    debug("Found configuration %o from %o.", config.filepath, dirname);
  }
  return config;
}

export function* loadConfig(
  name: string,
  dirname: string,
  envName: string,
  caller: CallerMetadata | undefined,
): Handler<ConfigFile> {
  const filepath = require.resolve(name, { paths: [dirname] });

  const conf = yield* readConfig(filepath, envName, caller);
  if (!conf) {
    throw new ConfigError(
      `Config file contains no configuration data`,
      filepath,
    );
  }

  debug("Loaded config %o from %o.", name, dirname);
  return conf;
}

/**
 * Read the given config file, returning the result. Returns null if no config was found, but will
 * throw if there are parsing errors while loading a config.
 */
function readConfig(
  filepath: string,
  envName: string,
  caller: CallerMetadata | undefined,
): Handler<ConfigFile | null> {

View on GitHub (pinned to 06b6eae39d)

Solutions

1. Open the config file referenced in the error and ensure it exports a non-empty config object or a function returning one.
2. If the file is a stub, populate it with at least { presets: [] } or remove the configFile option so Babel does not load it.
3. Verify the default export path (export default {...} for ESM, module.exports = {...} for CJS).

Example fix

// before - babel.config.js throws error 28
module.exports = undefined;

// after
module.exports = {
  presets: ['@babel/preset-env'],
};

const cfg = require(path.resolve('babel.config.js'));
const resolved = typeof cfg === 'function' ? cfg({ cache: () => {}, env: () => 'development' }) : cfg;
if (!resolved || (typeof resolved !== 'object')) {
  throw new Error('babel.config.js exports no configuration data');
}

function hasConfigData(value: unknown): value is Record<string, unknown> {
  return value != null && typeof value === 'object' && !Array.isArray(value);
}

try { babel.loadOptionsSync({ configFile: './babel.config.js' }); }
catch (err) {
  if (/Config file contains no configuration data/.test(err.message)) {
    console.error(err.filename, 'exports undefined/null - add a default export');
  }
  throw err;
}

When it happens

Trigger: Pointing the `configFile` option or a programmatic load at a module that exports nothing (module.exports = undefined), exports an empty object that readConfigCode rejects, or a JS config whose factory returns null. Also when require.resolve finds a file but its content does not yield a config.

Common situations: Setting `configFile: './babel.config.js'` where that file is empty or exports undefined; config file left as a stub during scaffolding; circular/failed default export.

Related errors

• .babel property must be an object
• No config detected
• Config returned typeof ${typeof options}
• Expected config object but found array
• Negation of file paths is not supported.

AI-assisted analysis of babel/babel@06b6eae39d (2026-08-03). Data as JSON: /data/errors/6c64ca940398aa0f.json. Report an issue: GitHub.