Query string parser and manipulation.

url-parse.js

function parseUrl (url) {
  var a = document.createElement('a')
  a.setAttribute('href', url)
  var search = a.search
  var query = {}
  var kvs = search.split(/[\?&]/g)
  kvs.forEach(function (kv) {
    kv = kv.split('=')
    if (kv.length === 2) {
      query[kv[0]] = kv[1]
    }
  })
  return {
    get: function (k) {
      return query[k]
    },
    set: function (k, v) {
      query[k] = v
    },
    stringify: function () {
      var i = 0
      var search = ''
      for (var key in query) {
        var prefix = i === 0 ? '?' : '&'
        search += prefix + key + '=' + query[key]
        i++
      }
      return search
    }
  }
}