如何从JavaScript检查会话是否存在

Question

I'm using NodeJs + Ejs and sometimes I would like to do some stuff from JavaScript only if user session exists.

Here is my nodejs session part:

var express  = require('express');
var app      = express();
var session  = require('express-session');

app.use(session({
    secret: '*********',
    maxAge: 3600000 
}));
app.use(function(req, res, next){
    res.locals.session = req.session;
    next();
});

I can see session exists from ejs when, for example, Jack is logged in:

User: <%= session.user.name %>  --> User: Jack

But I don't know how to check if session.user exists from javascript. For example how to show alert if session.user exists ?

Answer 1

Simply tell it to the client side:

<script>
 const user = "<%= session.user.name %>";
 if(user) alert(user);
</script>