exemple3.js

function createUserAndCompany(userCompany) {
    return sequelize.transaction((registerTrans) => {
        return new Promise((resolve, reject) => {
            const { user, company} = userCompany;
            User.create(user)
                .then((newUser) => {
                    Company.create({...company,idUser: newUser.id})
                    .then((newCompany) => {
                        EventEmitter.emit('USER_CREATED', {user:newUser}); // HERE IS THE PROBLEM
                        EventEmitter.emit('COMPANY_CREATED', {company: newCompany}); // OR HERE
                        resolve() // Promise is resolved so the transaction should be commited
                    })
                    .catch((err)=>reject(err)) // Promise is rejected so transaction is rolled back
                })
                .catch((err) => reject(err)); // Promise is rejected so transaction is rolled back
        })
    });
}