why is passport local mongoose use code example

Example 1: passport local mongoose

const User = require('./models/user'); 
// CHANGE: USE "createStrategy" INSTEAD OF "authenticate"
passport.use(User.createStrategy()); 
passport.serializeUser(User.serializeUser());
passport.deserializeUser(User.deserializeUser());

Example 2: npm passport-local-mongoose

require('dotenv').config()