How does the express framework get the interface? session, already exists in the interface. Session, writes the interface in express, but you can't call it when you put the project in express.

to make a website, you need to use single sign-on, the front end is built with vue-cli, and then use build to package the project and put it in express and forward it through express. But because single sign-on is successful, it will jump directly to my index.html, so I don"t know how to get the directory structure of token
express returned to me by the front-end page in the express route:

index.htmlvue

loginindex
vue-cliindex.html:

oidc-client.jsjs
login.jsjs

sessionsession Storageexpress:

asked my colleagues at the lower back end. They said that webserver generally receives values by sending requests in the page. I wrote the following code

in the app.js of express.

app.post("/user/login", function(req, res) {
    res.status(200)
    res.json({ message: "Token" })
    console.log(req)
})

the code called in the login method in the project"s login.js is as follows:

function log() {

    Array.prototype.forEach.call(arguments, function(msg) {
        if (msg instanceof Error) {
            msg = "Error: " + msg.message;
        } else if (typeof msg !== "string") {
            msg = JSON.stringify(msg, null, 2);
        }
        console.log(msg)
        
        //sessionexpress
        var ajax = new XMLHttpRequest();
        ajax.setRequestHeader("Content-type", "application/json");
        ajax.open("post", "...");
        ajax.send(msg)
        console.log(ajax.status);
    });
}

but after running like this, single sign-on will not work, and the forwarding layer in the middle of express, has not been used for the first time. I would like to ask you to be familiar with the mistakes made by Daniel in express, or a better and more reasonable way to get the information in session Storage. Thank you