JAVASCRIPT

converting circular structure to json

check if you have not added async and await

full problem can be like this:
Converting circular structure to JSON
    --> starting at object with constructor 'MongoClient'
    |     property 's' -> object with constructor 'Object'
    |     property 'sessionPool' -> object with constructor 'ServerSessionPool'
    --- property 'client' closes the circle

Converting circular structure to JSON

//The error means that the object you pass in the request has a circular reference, something like:

var a = {};
a.b = a;

converting circular structure to json

var win = window.open('http://www.google.com', 'google','width=800,height=600,status=0,toolbar=0'); 
var timer = setInterval(function() { 
    if(win.closed) {
        clearInterval(timer);
        alert('closed');
    }
}, 1000);

TypeError: Converting circular structure to JSON

I run into this issue, because i was sending as response the full response of another api call instead of just the data i needed.