How to share sequelize connection over node js files?

Question

I am trying to make MVC project with node js and sequelize (mysql).

Now I have made the connection to database in the index.js

index.js

const express = require('express')
const msyql = require ('mysql')
const app = express()
const Sequelize = require ('sequelize')

app.set("view engine", "ejs")
app.use(express.static('public'))


app.listen(3000, ()=> {
    console.log ("Server is running on 3000")
})

// routes

const homeRoute = require('./routes/homeRoute.js')
app.use(homeRoute)

// db confg

const db = new Sequelize ('maxDev', 'root', '', {
    host: '127.0.0.1',
    dialect: 'mysql'
})

db.authenticate().then(()=>{
    console.log("DB connected!")

}).catch(error=>{
    throw error
})

// 


module.exports = db

At line 16: it will import the model that will also Import the migrtation and inside the migration file it will import the db which we have declared in index.js file.

but when I start the execution it gives me the error C:\Users\hmada\Desktop\maxSite\migrations\products.js:4 const Products = db.define('Products', { ^

TypeError: db.define is not a function

I realize that the db.authenticate return a promise so it should take some time before using so What should i do know ??

model file

const Products = require('.././migrations/products.js')

function getMainProducts () {
    const sql = "SELECT * FROM products"
    conn.query(sql, (err, result)=>{
        if (err) return console.log(err)
        return console.log(result)
    })
}

module.exports = {
    getMainProducts,
}

migration file

const {Sequelize, DataTypes} = require('sequelize')
const db = require('.././index.js')

const Products = db.define('Products', {
    id: {
        type: DataTypes.INTEGER,
        allowNull:false,
        primaryKey: true
    },

    name: {
        type: DataTypes.STRING,
        allowNull:false
    },

    price: {
        type: DataTypes.STRING,
        allowNull:false
    },

    specs: {
        type:DataTypes.STRING,
        allowNull: false
    },

    imgUrl: {
        type: DataTypes.TEXT,
    }

})

db.sync().then ().catch (error=> {
    throw error
})

module.exports = Products