socket.io-client Converting circular structure to JSON --> starting at object with constructor

The error "Converting circular structure to JSON" occurs when you are trying to stringify an object that contains circular references, meaning there is a loop in the object's structure. JSON does not support circular references, so when you try to convert such an object to JSON, you will encounter this error.

To resolve this issue, you need to identify and break the circular reference in your object before converting it to JSON. One approach is to remove or replace the circular reference with a placeholder value or an identifier that can be restored later.

In the case of `socket.io-client`, the circular reference error can occur if you are trying to emit or send an object that contains circular references through a socket. You can use the `JSON.stringify` method with a replacer function to handle circular references:

const circularReplacer = () => {
  const seen = new WeakSet();
  return (key, value) => {
    if (typeof value === "object" && value !== null) {
      if (seen.has(value)) {
        return;
      }
      seen.add(value);
    }
    return value;
  };
};

const jsonString = JSON.stringify(yourObject, circularReplacer());

This replacer function uses a `WeakSet` to keep track of visited objects and ignores circular references by returning undefined for them.

Make sure to apply this replacer function to your object before sending it through `socket.io-client`.