format url

import * as querystring from 'querystring';

function isObject(arg: any) {
  return typeof(arg) === 'object' && arg !== null;
}

const slashedProtocol = {
  http: true,
  https: true,
  ftp: true,
  gopher: true,
  file: true,
  ws: true,
  wss: true,
  'http:': true,
  'https:': true,
  'ftp:': true,
  'gopher:': true,
  'file:': true,
  'ws:': true,
  'wss:': true,
}

interface FormatUrlArgs {
  protocol?: string,
  slashes?: string,
  auth?: string,
  host?: string,
  port?: string,
  hostname?: string,
  hash?: string,
  search?: string,
  query?: string,
  pathname?: string,
  path?: string,
  href?: string,
}

// tslint:disable-next-line:cyclomatic-complexity
function formatUrl(url: FormatUrlArgs) {
  let auth = url.auth || '';
  if (auth) {
    auth = encodeURIComponent(auth);
    auth = auth.replace(/%3A/i, ':');
    auth += '@';
  }

  let protocol = url.protocol || '';
  let pathname = url.pathname || '';
  let hash = url.hash || '';
  let host = url.host || '';
  let query = '';

  if (url.host) {
    host = auth + url.host;
  } else if (url.hostname) {
    host = auth + (typeof url.hostname === 'string' && url.hostname.indexOf(':') === -1 ?
        url.hostname :
        '[' + url.hostname + ']');
    if (url.port) {
      host += ':' + url.port;
    }
  }

  if (url.query && isObject(url.query) && Object.keys(url.query).length) {
    query = querystring.stringify(url.query);
  }

  let search = url.search || (query && ('?' + query)) || '';

  if (protocol && protocol.substr(-1) !== ':') {
    protocol += ':'
  }

  // only the slashedProtocols get the //.  Not mailto:, xmpp:, etc.
  // unless they had them to begin with.
  if (url.slashes ||
      (!protocol || slashedProtocol[protocol])) {
    host = '//' + (host || '');
    if (pathname && pathname.charAt(0) !== '/') {
      pathname = '/' + pathname;
    }
  } else if (!host) {
    host = '';
  }

  if (hash && hash.charAt(0) !== '#') {
    hash = '#' + hash;
  }
  if (search && search.charAt(0) !== '?') {
    search = '?' + search;
  }

  pathname = pathname.replace(/[?#]/g, match => {
    return encodeURIComponent(match);
  });
  search = search.replace('#', '%23');

  return protocol + host + pathname + search + hash;
};