function parse (jsonString) {
  try {
    return JSON.parse(jsonString)
  } catch (err) {
    // try to throw a more detailed error message using validate
    validate(jsonString)

    // rethrow the original error
    throw err
  }
}
Parse JSON using the parser built-in in the browser.
On exception, the jsonString is validated and a detailed error is thrown.
@param {String} jsonString
@return {JSON} json