How to get Last inserted id using Nodejs

I am working with Nodejs and i am using expressjs framework,Right now i am trying to get
"last inserted id" but i am getting "undefined" in console, How can i get last inserted id ? Here is my current code

static async addServiceDetail(salonId,serviceId,genderTypeId,price,serviceName)
    {
        const sql = `SELECT id from hc_servicesdetail WHERE shopId='${shopId}' AND  serviceId='${serviceId}' AND genderTypeId='genderTypeId'`;
        const [rows, fields] = await pool.execute(sql);
        if(rows<1)
            {
                const sql2 = `INSERT INTO hc_servicesdetail (shopId, serviceId, genderTypeId,price,serviceName) VALUES ("${shopId}", "${serviceId}", "${genderTypeId}", "${price}","${serviceName}")`;
                const datass = await pool.execute(sql2);
                console.log('last inserted id is ' +datass.insertId);
            }
        else
            {
                console.log('already exist');
            }   
    }
}

module.exports = User;

>Solution :

Use the result.insertId property. This property is available in the callback function that gets executed when you perform an INSERT query.

static async addServiceDetail(shopId, serviceId, genderTypeId, price, serviceName) {
    const sql = `SELECT id from hc_servicesdetail WHERE shopId='\${shopId}' AND  serviceId='\${serviceId}' AND genderTypeId='\${genderTypeId}'`;
    const [rows, fields] = await pool.execute(sql);
    if (rows < 1) {
        const sql2 = `INSERT INTO hc_servicesdetail (shopId, serviceId, genderTypeId, price, serviceName) VALUES ("\${shopId}", "\${serviceId}", "\${genderTypeId}", "\${price}","\${serviceName}")`;
        const [datass, _] = await pool.execute(sql2);
        console.log('last inserted id is ' + datass.insertId);
    } else {
        console.log('already exist');
    }
}

Notice that I changed genderTypeId='genderTypeId' to genderTypeId='\${genderTypeId}' in the first SQL query. This should fix a syntax error.