How cookies work? 
Post /login
201 ok; Cookie: USERID=1234
Get /posts; Cookie USERID=1234
Posts.hbs, {post data}

How to write cookies? 
app.get(“/”, function(req,res){
res.cookie(“foo”, “bar”, {
	maxAge: 60*60*1000,
	httpOnly: true
})
})
“Foo” is the name of the cookie 
“Bar” is the value of the cookie 
maxAge, expiry time relative to current time in milliseconds 
httpOnly, Flags the cookie to be only accessible by the web server, make the cookie inaccessible if used through document.cookie 
https://expressjs.com/en/5x/api.html#res.cookie

How to read cookies? 
npm install cookie-parser
const cookieparser 
= require(“cookie-parser”)
app.use(cookieparser())
app.get(“/”, function(req,res){
let cookiefoo = req.cookies.foo
if(cookiefoo){
console.log(“foo: “ + cookiefoo)
}
})
Install Cookie Parser
Import Cookie Parser

How sessions work? 
Post /login
201 ok; Cookie: SESSIONID=1234
Get /posts; Cookie SESSIONID=1234
Posts.hbs, {post data}
1234 : {
    Userid: 123,
    Usertype: “customer”
}

How to read/write sessions? 
https://github.com/expressjs/session  
app.get(“/”, function(req,res){
req.session.foo = “bar”
})
npm install express-session
app.use(session({
secret: “very super secret”,
resave: false,
saveUninitialized: true,
cookie: {
	maxAge:1000*60*60*24*30
	httpOnly: true
}
}))
const session = require(“express-session”)
Install Express Session
Import Express Session
Secret, used to sign the session ID cookie. This prevents users from being a sus
Resave, forces the session to be saved back to the session store even if  session was never modified 
SaveUninitialized, Forces a session that is uninitialized to be saved to the store
Cookie, Cookie properties are set here