使用 Node.js 将对象转换为字符串时出现类型错误

Question

I am getting the following error while trying to convert object to string using Node.js/JavaScript:

TypeError: Converting circular structure to JSON
    at Object.stringify (native)
    at exports.userlogin (/opt/lampp/htdocs/FGDP/route/route.js:11:19)
    at Layer.handle [as handle_request] (/opt/lampp/htdocs/FGDP/node_modules/express/lib/router/layer.js:95:5)
    at next (/opt/lampp/htdocs/FGDP/node_modules/express/lib/router/route.js:131:13)
    at Route.dispatch (/opt/lampp/htdocs/FGDP/node_modules/express/lib/router/route.js:112:3)
    at Layer.handle [as handle_request] (/opt/lampp/htdocs/FGDP/node_modules/express/lib/router/layer.js:95:5)
    at /opt/lampp/htdocs/FGDP/node_modules/express/lib/router/index.js:277:22
    at Function.process_params (/opt/lampp/htdocs/FGDP/node_modules/express/lib/router/index.js:330:12)
    at next (/opt/lampp/htdocs/FGDP/node_modules/express/lib/router/index.js:271:10)

I am providing my code below:

exports.userlogin=function(req,res){
    var username=req.body.user_name;
    var password=req.body.user_pass;
    var ciphertext = CryptoJS.AES.encrypt(password, 'lexelPass');
    var pass=JSON.stringify(ciphertext);
}

Here I am getting ciphertext variables datatype is object and I need it to convert into string. But here I am getting this type of error.

Answer 1

Object return by CryptoJS.AES.encrypt(password, 'lexelPass') statement is of Circular type. Circular type are something like

 var obj = {}; obj.obj = obj;

So for tackling this thing we can utilize replacer callback function in JSON.stringify as a second parameter. By putting logic for discarding the circular object in replacer function.

check syntax at MDN for replacer

Answer 2

You likely want to convert the ciphertext into a string using the WordArray.toString([encoding]) method.

var pass = ciphertext.toString();

If you really want to stringify the WordArray you can use util.inspect(object[, options]) which automatically replaces circular references with the string [Circular] instead of throwing an error, but keep in mind that util.inspect is specific to Node.