text: // Attempt to convert a string value to a Boolean. Otherwise, return the value
  // without modification so Vue can throw a warning.
  export default (val) => (typeof val !== 'string' ? val
    : val === 'true' ? true
    : val === 'false' ? false
    : val === 'null' ? false
    : val === 'undefined' ? false
    : val)
  