code: function pton4(addr, dest, index = 0) {
    if (typeof addr !== 'string') {
      throw new TypeError('Argument 1 should be a string.')
    }
  
    if (arguments.length >= 3) {
      if (typeof index !== 'number') {
        throw new TypeError('Argument 3 should be a Number.')
      }
    }
  
    const isbuffer = Buffer.isBuffer(dest)
  
    if (isbuffer) {
      if (index + IPV4_OCTETS > dest.length) {
        throw new Error('Too small target buffer.')
      }
    }
  
    const buf = isbuffer ? dest : Buffer.allocUnsafe(IPV4_OCTETS)
  
    let octets = 0
    let sawDigit = false
    let number = 0
  
    for (let i = 0; i < addr.length; ++i) {
      const char = code(addr[i])
  
      if (isDigit(char)) {
        number = (number * 10) + (char - CHAR0)
  
        if (sawDigit && number === 0) {
          einval()
        }
  
        if (number > 0xFF) {
          einval()
        }
  
        if (!sawDigit) {
          if (++octets > IPV4_OCTETS) {
            einval()
          }
          sawDigit = true
        }
      } else if (char === CHARPOINT && sawDigit) {
        if (octets === IPV4_OCTETS) {
          einval()
        }
  
        buf[index++] = number
        number = 0
        sawDigit = false
      } else {
        einval()
      }
    }
  
    if (octets < IPV4_OCTETS) {
      einval()
    }
  
    if (sawDigit) {
      buf[index] = number
    }
  
    return buf
  }
docs: Convert IPv4 to the Buffer.
  
  @param {string} addr
  @param {Buffer} [dest]
  @param {number} [index=0]
  @returns {Buffer}