AngularJS $ http和过滤器

I have a JSON file, which contains:

{
  "/default.aspx": "headerBg",
  "/about.aspx": "aboutBg",
  "/contact.aspx": "contactBg",
  "/registration.aspx": "regBg",
  "/clients.aspx": "clientsBg",
  "/onlinesessions.aspx": "bg-white-box",
  "/ondemamdsessions.aspx": "bg-grey"
}

Now I am reading this json file using $http, but I want to add a filter in below fashion:

Using window.location.pathname, I am reading path of the current page, suppose the current page is /about.aspx

Then I want to add a filter in $http response by which I want to read only aboutBg.

The code I wrote can retrieve all the values, but unable to filter that. Please help.

1. there is no direct method to get key using value from json.
2. you should make sure that there are no 2 keys having same value for below code to work

function swapJsonKeyValues(input) {
    var one, output = {};
    for (one in input) {
        if (input.hasOwnProperty(one)) {
            output[input[one]] = one;
        }
    }
    return output;
}
var originaJSON = {
  "/default.aspx": "headerBg",
  "/about.aspx": "aboutBg",
  "/contact.aspx": "contactBg",
  "/registration.aspx": "regBg",
  "/clients.aspx": "clientsBg",
  "/onlinesessions.aspx": "bg-white-box",
  "/ondemamdsessions.aspx": "bg-grey"
}
var invertedJSON = swapJsonKeyValues(originaJSON);
var samplepathname = "aboutBg";
var page = invertedJSON[samplepathname];

[function swapJsonKeyValues from https://stackoverflow.com/a/1970193/1006780 ]

User this function where you receive the response.

function getPageBgClass(currentPage, responseData) {

    if (responseData.hasOwnProperty(currentPage))
       return responseData[currentPage]
    else
       return "none"
}

Here is how it should be used in your promise then function

function(response) {

     var bg = getPageBgClass(window.location.pathname, response.data);

     //Your code here ...
}