URL parsing with HTMLAnchorElement

parseUrl.js

const RE_URL_ARRAY = /\[(.*?)\]$/
export function parseQuery(search) {
  search = search.replace(/^\?/, '')
  let query = {}
  search.split('&').forEach(pair => {
    let kv = pair.split('=')
    let key = kv[0]
    let value = kv[1]
    if (!value) value = ''
    value = decodeURIComponent(value)
    let match = key.match(RE_URL_ARRAY)
    if (match) {
      key = key.replace(RE_URL_ARRAY, '')
      let subkey = match[1]
      if (subkey) {
        let dict = query[key] || (query[key] = {})
        dict[subkey] = value
      } else {
        let array = query[key] || (query[key] = [])
        array.push(value)
      }
    } else {
      query[key] = value
    }
  })
  return query
}

const _a = document.createElement('a')
export function parseUrl(url) {
  // ftp://user:pass@example.com:8080/root/sub/filename?foo=bar&arr[]=1&arr[]=2&kv[foo]=f&kv[bar]=b&empty=&single#hash
  _a.href = url

  return {
    protocol: _a.protocol,
    host: _a.host,
    hostname: _a.hostname,
    port: _a.port,
    username: _a.username,
    password: _a.password,
    pathname: _a.pathname,
    search: _a.search,
    query: parseQuery(_a.search),
    hash: _a.hash
  }
}