Store an instance in Express js session

问题:

I'm using the expressjs session, and I have a instance need to store:

function a(){this.name="";}
var ins = new a();
req.session['user'] = ins;

and when I get res.session['user'] next time, the object is not instanceof a, and it cannot access any prototype methods in a, how can i store the ref of the object in session, looks the session will convert it to json object

回答1:

You can't store instances like that in JSON unless:

• You provide your own custom serializer (implementing a toJSON() function in your class/object)
• You also identify your serialized object and instantiate a new instance in the reviver function you pass to JSON.parse().

回答2:

One thing you can do is create an instances/session map which you can identify via the session.id, I blogged about this here:

https://tomblanchard.co.uk/storing-instances-in-express-sessions/