Function loadJSConfigFile

src/config.js:119–182

(filePath)

}

export async function loadJSConfigFile(filePath) {
  const resolvedFilePath = path.resolve(filePath);
  log.debug(
    `Loading JS config file: "${filePath}" ` +
      `(resolved to "${resolvedFilePath}")`,
  );

  if (filePath.endsWith('.js')) {
    throw new UsageError(
      ` Invalid config file "${resolvedFilePath}": the file extension should be` +
        '".cjs" or ".mjs". More information at: https://mzl.la/web-ext-config-file',
    );
  }

  let configObject;
  try {
    const nonce = `${Date.now()}-${Math.random()}`;

    let configModule;
    if (resolvedFilePath.endsWith('package.json')) {
      configModule = parseJSON(
        await fs.readFile(resolvedFilePath, { encoding: 'utf-8' }),
      );
    } else {
      configModule = await import(`file://${resolvedFilePath}?nonce=${nonce}`);
    }

    if (configModule.default) {
      const { default: configDefault, ...esmConfigMod } = configModule;
      // ES modules may expose both a default and named exports and so
      // we merge the named exports on top of what may have been set in
      // the default export.
      if (filePath.endsWith('.cjs')) {
        // Remove the additional 'module.exports' named export that Node.js >=
        // 24 is returning from the dynamic import call (in addition to being
        // also set on the default property as in Node.js < 24).
        delete esmConfigMod['module.exports'];
      }
      configObject = { ...configDefault, ...esmConfigMod };
    } else {
      configObject = { ...configModule };
    }
  } catch (error) {
    const configFileError = new UsageError(
      `Cannot read config file "${resolvedFilePath}":\n${error}`,
    );
    configFileError.cause = error;
    throw configFileError;
  }

  if (filePath.endsWith('package.json')) {
    log.debug('Looking for webExt key inside package.json file');
    configObject = configObject.webExt || {};
  }

  if (Object.keys(configObject).length === 0) {
    log.debug(
      `Config file ${resolvedFilePath} did not define any options. ` +