pad_spa/node_modules/requires-port/index.js

'use strict';

/**
 * Check if we're required to add a port number.
 *
 * @see https://url.spec.whatwg.org/#default-port
 * @param {Number|String} port Port number we need to check
 * @param {String} protocol Protocol we need to check against.
 * @returns {Boolean} Is it a default port for the given protocol
 * @api private
 */
module.exports = function required(port, protocol) {
  protocol = protocol.split(':')[0];
  port = +port;

  if (!port) return false;

  switch (protocol) {
    case 'http':
    case 'ws':
    return port !== 80;

    case 'https':
    case 'wss':
    return port !== 443;

    case 'ftp':
    return port !== 21;

    case 'gopher':
    return port !== 70;

    case 'file':
    return false;
  }

  return port !== 0;
};