postgresql connect and test use pg module

dbInfo.json

{
    "user" : "{{USER_NAME}}",
    "userPW" : "{{USER_PASSWORD}}",
    "host" : "{{DB_HOST}}",
    "dbName" : "{{DB_NAME}}",
    "port" : "{{PORT}}"
}

postgresqlConnect.js

const {Client} = require('pg'),
      fs = require('fs');
      
var client;

module.exports = {
    settingDbConnection : function () {
        const thisApp = this;
        fs.readFile('./dbInfo.json', function(err, data){
            if(err) {
                console.log(err);
                return;
            }
            let dbInfoData = JSON.parse(data);
            client = new Client({
                user : dbInfoData.user,
                password : dbInfoData.userPW,
                host : dbInfoData.host,
                database : dbInfoData.dbName,
                port : dbInfoData.port
            });
            thisApp.connectionDB();
        });
    },
    connectionDB : function () {
        client.connect();
        client.query('{{QUERRY}}', (err, result) => {
            if(!err) {
                console.log(err);
            }
            console.log(result);
            client.end();
        });
    }
}