Give error for incorrect maxAge and expires Type

Out of mere developer error, I inserted into the maxAge field what should have been entered in expires:

maxAge : new Date(Date.now() + 3600000)

Instead of

expires : new Date(Date.now() + 3600000)

However this causes a weird quirk in creating a session, for example, setting username and password within seconds of eachother will create two sessions, each with a negative maxAge

{
"_id" : "zY02IMuLO720J-SLFKVj"
    "session" : {
        "cookie" : {
            "originalMaxAge" : -104023,
            "expires" : ISODate("..."),
            "secure" : null,
            "httpOnly" : true,
            "domain" : null,
            "path" : "/"
        },
                "username" : "username"
    },
}

"_id" : "fJ92IErLO730J-sLPMvQ"
    "session" : {
        "cookie" : {
            "originalMaxAge" : -104035,
            "expires" : ISODate("..."),
            "secure" : null,
            "httpOnly" : true,
            "domain" : null,
            "path" : "/"
        },
                "password" : "hashed_password"
    },
}

So they are set as separate sessions, and this causes a session to expire, and new session to be created immediately, having some functionality to have express-session throw an error if the wrong type is entered would be beneficial.

[dougwilson]

Ah @jackycute, good catch on the readme. That came from the cookie module and doesn’t fit well here. Let’s move the rest of this conversation to a new issue, please, so we don’t loose what the original issue was about.

[dougwilson]

This is the same issue @jackycute and I are running into, yep — I think more of a “weird behavior” report than a feature request, but agreed

Well, the thing is, JavaScript can change a Date object into a number without issue. Really, the weird behavior is JavaScript itself that you are describing 😃 You’re welcome to create a PR to increase the strictness of validating the input values, though!

our issue is the session originalMaxAge is set to be a negative number. and I did pass a Date object to expries, I don’t know if that is not appropriate.

I’m not certain what happens if you are setting both maxAge and expires. I think they are supposed to be mutually exclusive. Does removing expires fix the issue? Perhaps we can open a new issue regarding that behavior as well.