Slashes in json returned from node

Question

I am getting slashes in the json returned from Node server. This is giving challenges in parsing the json.

The json looks like

"{\"responseCode\":200,\"headers\":{\"Access-Control-Allow-Origin\":\"*\",\"Content-Type\":\"application/json; charset=utf-8\",\"X-Powered-By\":\"Express\",\"Connection\":\"keep-alive\",\"Date\":\"Thu, 22 Sep 2016 08:12:39 GMT\",\"Content-Length\":\"21\",\"Etag\":\"W/\\"15-HeifZ4bmt+WxpIWDoartGQ\\"\"},\"response\":\"{\\"status\\":\\"UP\\"}\",\"bytesSent\":715779}"

In order to get rid of the slashes, I did a replace and then converted it back to json using JSON.parse

.then(function (result) {
     var status = "";
     var str = JSON.stringify(result); 
     console.log("str result  ", str);
     str = str.replace(/\\/g, "");
     console.log("result after cleanup  ", str);
     var obj = JSON.parse(str);
     status = obj.response.status;
}

After replacing the slashes, the string looks like this

"{\"responseCode\":200,\"headers\":{\"Access-Control-Allow-Origin\":\"*\",\"Content-Type\":\"application/json; charset=utf-8\",\"X-Powered-By\":\"Express\",\"Connection\":\"keep-alive\",\"Date\":\"Thu, 22 Sep 2016 08:12:39 GMT\",\"Content-Length\":\"21\",\"Etag\":\"W/\"15-HeifZ4bmt+WxpIWDoartGQ\"\"},\"response\":\"{\"status\":\"UPLOADED\"}\",\"bytesSent\":715779}"

When I try to parse it to JSON object, it throws an error on

var obj = JSON.parse(str);

It seems that the JSON is still invalid due to the slashes which still exist.

I have the following queries -

1. How can I update my regex to get rid of these slashes as well
2. Why do these slashes get introduced in the response

Answer 1

JSON.stringify() is the method used to generate a JSON string. If you apply it to something that's already a JSON string then you'll get a double-encoded JSON string:

var alreadyJson = '{"foo": "bar"}';
var doubleEncoded = JSON.stringify(alreadyJson);
console.log(doubleEncoded , typeof doubleEncoded);

"{\"foo\": \"bar\"}" string

What you need to use is the JSON.parse() method:

var alreadyJson = '{"foo": "bar"}';
var decoded = JSON.parse(alreadyJson);
console.log(decode, typeof decoded);

{ foo: 'bar' } 'object'