code: function shouldProxy(hostname, port) {
    var NO_PROXY = getEnv('no_proxy').toLowerCase();
    if (!NO_PROXY) {
      return true;  // Always proxy if NO_PROXY is not set.
    }
    if (NO_PROXY === '*') {
      return false;  // Never proxy if wildcard is set.
    }
  
    return NO_PROXY.split(/[,\s]/).every(function(proxy) {
      if (!proxy) {
        return true;  // Skip zero-length hosts.
      }
      var parsedProxy = proxy.match(/^(.+):(\d+)$/);
      var parsedProxyHostname = parsedProxy ? parsedProxy[1] : proxy;
      var parsedProxyPort = parsedProxy ? parseInt(parsedProxy[2]) : 0;
      if (parsedProxyPort && parsedProxyPort !== port) {
        return true;  // Skip if ports don't match.
      }
  
      if (!/^[.*]/.test(parsedProxyHostname)) {
        // No wildcards, so stop proxying if there is an exact match.
        return hostname !== parsedProxyHostname;
      }
  
      if (parsedProxyHostname.charAt(0) === '*') {
        // Remove leading wildcard.
        parsedProxyHostname = parsedProxyHostname.slice(1);
      }
      // Stop proxying if the hostname ends with the no_proxy host.
      return !stringEndsWith.call(hostname, parsedProxyHostname);
    });
  }
docs: Determines whether a given URL should be proxied.
  
  @param {string} hostname - The host name of the URL.
  @param {number} port - The effective port of the URL.
  @returns {boolean} Whether the given URL should be proxied.
  @private