Function getDate

lib/handler/cache-handler.js:558–573

* @param {string | string[]} dateHeader * @returns {Date | null | undefined}

(dateHeader)

 * @returns {Date | null | undefined}
 */
function getDate (dateHeader) {
  let dateValue = dateHeader
  if (Array.isArray(dateValue)) {
    if (dateValue.length !== 1) {
      return null
    }

    dateValue = dateValue[0]
  }

  if (typeof dateValue !== 'string') {
    return null
  }

  return parseHttpDate(dateValue)
}

/**
 * @param {string | string[]} ageHeader