Can't add new command when connection is in closed state

[Shubh0817]

I am using mysql2 driver to connect MySql Database with below config

mysql.createPool({
host: process.env.NODE_MYSQL_IP,
user: process.env.MYSQL_USER,
password: decryptPassword(process.env.NODE_MYSQL_PASSWORD),
database: process.env.MYSQL_SCHEMA,
waitForConnections: true,
connectionLimit: 4, // 20 concurrent connections
maxIdle: 4, // max idle connections, the default value is the same as connectionLimit
idleTimeout: 20000, // idle connections timeout, in milliseconds, the default value 60000
queueLimit: 0
});

I am using execute method instead of query.

when i have to just perform select query then i directly use pool but when i have to start transaction then i get connection from pool and then commit and release respectively.

also i have printed free connection with all connection as below code

const allConnections = connection.pool?._allConnections.length ?? connection.connection._pool?._allConnections.length;
const freeConnections = connection.pool?._freeConnections.length ?? connection.connection._pool?._freeConnections.length;

my allConnections become 0 after some time and then i got error as Error: Can't add new command when connection is in closed state on execute method.

please help