hackish-url-parser.js

// @flow

import {
  always,
  memoize,
  pick,
} from "ramda";

type ParsedURL = {
  protocol: string,
  host: string,
  port: number,
  search: string,
  hash: string,
  pathname: string,
  toString: void => string,
}

export const parseUrl: string => ParsedURL = memoize(url => {
  const parser = document.createElement("a");
  parser.href = url;

  return {
    ...pick(["protocol", "host", "port", "search", "hash"], parser),
    
    // IE doesn't add a slash at the beginning of the path name
    pathname: parser.pathname.startsWith("/") ? parser.pathname : "/" + parser.pathname,
    
    // We must call the `toString` instead of using it inside a closure,
    // so the DOM element can be garbage collected
    toString: always(parser.toString()),
  };
});