EXPRESS SESSIONS

 LET'S TAKE AMAZON SHOPPING WEBSITE FOR EXAMPLE, HERE AN USER CAN ADD ITEMS TO CART WITHOUT LOGGIN IN OR SIGN UP.

IF THE USER VISITS ELECTRONIC SECTION AND ADDS SOME ITEMS TO CART AND MOVES TO NEXT PAGE CLOTHING SECTION AND TRIES TO ADD CLOTHING ITEMS TO CART.

HERE WHEN THE USER MOVES TO THE 2ND PAGE, THE ITEMS ADDED IN THE 1ST PAGE ARE NOT KNOWN TO THE BROWSER WHEN THE 2ND PAGE IS LOADED.

INORDER TO SOLVE THIS ISSUE,WE USE EXPRESS-SESSIONS.

IN EXPRESS-SESSIONS ,

=> TEMPORARY STORAGE IS USED(STORES THE ITEMS THAT ARE ADDED TO THE CART TEMPORARILY)

=> EACH SESSION HAS A SESSION ID ,THIS ID IS STORED IN A COOKIE IN THE BROWSER,

SO THAT THE BROWSER KNOWS THE ITEMS THAT ARE ADDED IN THE 1ST PAGE.

TO INSTALL EXPRESS-SESSION: npm i express-session

const session = require("express-session");

app.use(session({ secret: "secretstring" }));

app.get("/test", (req, res) => {

  res.send("test successful");

});

HERE, SESSION ID IS STORED IN THE COOKIE , NOW EVERY ROUTE IN THE WEBSITE HAS IT.