How can javascript parse a Rails generated query string with nested values into JSON?

Question

Rails allows the generation of query strings by passing a hash to a url_for type helper:

root_path({ :animals => {:dogs => ['pluto','spot'], :cats => 'garfield'} })

This will generate a url like:

http://example.com/?animals[dogs][]=pluto&animals[dogs][]=spot&animals[cats]=garfield

I want to use javascript to turn this into a JSON object so I have an object that matches the hash passed into the url helper in rails.

Using prototype.js I can call:

var params = window.location.search.toQueryParams();

params is a object but the original nested structure is not retained, instead I get:

{
  "animals[dogs][]" : ["pluto","spot"],
  "animals[cats]" : "garfield"
}

What I really want is:

{
  "animals" : {
    "dogs" : ["pluto","spot"],
    "cats" : "garfield"
  }
}

Also the reverse would be useful too. Prototype.js has toQueryString which in this case just returns an empty string:

Object.toQueryString({
  "animals" : {
    "dogs" : ["pluto","spot"],
    "cats" : "garfield"
  }
});

Is there a library of method that provides for this?

Answer 1

To answer my own question:

I found Ben Alman's jQuery BBQ which does it with a jQuery plugin.