async function isEsModule()

in src/loader.ts [49:66]

• 15 lines of code
• 3 McCabe index (conditional complexity)

async function isEsModule(modulePath: string): Promise<boolean> {
  const ext = path.extname(modulePath);
  if (ext === '.mjs') {
    return true;
  }
  if (ext === '.cjs') {
    return false;
  }

  const {readPackageUp} = await dynamicImport('read-package-up');
  const pkg = await readPackageUp({
    cwd: path.dirname(modulePath),
    normalize: false,
  });

  // If package.json specifies type as 'module', it's an ES module.
  return pkg?.packageJson.type === 'module';
}