function status (code) {
  if (typeof code === 'number') {
    return getStatusMessage(code)
  }

  if (typeof code !== 'string') {
    throw new TypeError('code must be a number or string')
  }

  // '403'
  var n = parseInt(code, 10);
  if (!isNaN(n)) {
    return getStatusMessage(n)
  }

  return getStatusCode(code)
}
Get the status code.

Given a number, this will throw if it is not a known status
code, otherwise the code will be returned. Given a string,
the string will be parsed for a number and return the code
if valid, otherwise will lookup the code assuming this is
the status message.

@param {string|number} code
@returns {number}
@public