Easy scope value to location mapping with friendly names. Use this inside an angular controller.

gistfile1.coffee

# scope to url query part mapping ( #!/?key=val )
queryMapping =
    category: 'cat'
    searchQuery: 'q'
    'selected.id': 'show'
query = $location.search()
for key, queryKey of queryMapping
    # initially set scope values to query params
    if queryKey of query
        $scope[key] = query[queryKey]
    # add watchers
    $scope.$watch key, do ->
        _key = queryKey
        (newValue, oldValue) ->
            q = $location.search()
            if newValue? and newValue != ''
                q[_key] = newValue
            else
                delete q[_key]
            $location.search(q)