code: function indexTemplate(format, data) {
    if (format === 'cjs') {
      return `module.exports = require('${data.main}')`
    }
    if (format === 'esm') {
      return `import ${data.name} from '${data.main}'
  
  export default ${data.name}`
    }
  }
docs: Utility functions.
  @private
   
  Create contents for an index.js file.
  @param {String} format The format to use. 'cjs' or 'esm'.
  @param {Object} data The data to use as part of the template.