Function parseImfDate

deps/undici/src/lib/util/date.js:27–229

* @see https://httpwg.org/specs/rfc9110.html#preferred.date.format * * @param {string} date * @returns {Date | undefined}

(date)

 * @returns {Date | undefined}
 */
function parseImfDate (date) {
  if (
    date.length !== 29 ||
    date[4] !== ' ' ||
    date[7] !== ' ' ||
    date[11] !== ' ' ||
    date[16] !== ' ' ||
    date[19] !== ':' ||
    date[22] !== ':' ||
    date[25] !== ' ' ||
    date[26] !== 'G' ||
    date[27] !== 'M' ||
    date[28] !== 'T'
  ) {
    return undefined
  }

  let weekday = -1
  if (date[0] === 'S' && date[1] === 'u' && date[2] === 'n') { // Sunday
    weekday = 0
  } else if (date[0] === 'M' && date[1] === 'o' && date[2] === 'n') { // Monday
    weekday = 1
  } else if (date[0] === 'T' && date[1] === 'u' && date[2] === 'e') { // Tuesday
    weekday = 2
  } else if (date[0] === 'W' && date[1] === 'e' && date[2] === 'd') { // Wednesday
    weekday = 3
  } else if (date[0] === 'T' && date[1] === 'h' && date[2] === 'u') { // Thursday
    weekday = 4
  } else if (date[0] === 'F' && date[1] === 'r' && date[2] === 'i') { // Friday
    weekday = 5
  } else if (date[0] === 'S' && date[1] === 'a' && date[2] === 't') { // Saturday
    weekday = 6
  } else {
    return undefined // Not a valid day of the week
  }

  let day = 0
  if (date[5] === '0') {
    // Single digit day, e.g. "Sun Nov 6 08:49:37 1994"
    const code = date.charCodeAt(6)
    if (code < 49 || code > 57) {
      return undefined // Not a digit
    }
    day = code - 48 // Convert ASCII code to number
  } else {
    const code1 = date.charCodeAt(5)
    if (code1 < 49 || code1 > 51) {
      return undefined // Not a digit between 1 and 3
    }
    const code2 = date.charCodeAt(6)
    if (code2 < 48 || code2 > 57) {
      return undefined // Not a digit
    }
    day = (code1 - 48) * 10 + (code2 - 48) // Convert ASCII codes to number
  }

  let monthIdx = -1
  if (