Use connection Postgresql on NodeJS (express)

I'm a novice at NodeJS and Express, I followed a tutorial to create a CRUD with a connection to Mysql where "express-myconnection" is used, that connection is recorded as middleware and is used from a model or controller. But I need to work with postgresql, I managed to make the connection, my problem is that I can not call it from a model or a controller

const express = require('express');
const path = require('path');
const morgan = require('morgan');
const app = express();
const { Client } = require('pg');
const connectionData = {
    user: 'postgres',
    host: 'localhost',
    database: 'bex',
    password: 'postgres',
    port: 5432,
}
const client = new Client(connectionData);
client.connect()
client.query('SELECT * FROM bex_usuario')
    .then(response => {
        console.log(response.rows)
        client.end()
    })
    .catch(err => {
        client.end()
    })

How would you create a middleware similar to "express-myconnection", or how would you instantiate from my model or controller without the need to define it in each model or controller?

Copyright License：
Author:「Wilmer」,Reproduced under the CC 4.0 BY-SA copyright license with link to original source & disclaimer.
Link to：https://stackoverflow.com/questions/53001022/use-connection-postgresql-on-nodejs-express