connection.js

var mysql = require('mysql');
var db; var setting = { host : "localhost", user : "root", password : "", database : "crudapp" };
function connectDatabase() {
  if(!db) {
    db = mysql.createConnection(setting);
    db.connect(function (err) {
      if(!err) {
        console.log("Database connected")
        ;
      }
      else {
        console.log("Error database connection")
      }
    })
  }
  return db;
}
module.exports = connectDatabase();