formValidation

function solve() {
        //Write your code here
        let userName = $('#username');
        let email = $('#email');
        let password = $('#password');
        let confPass = $('#confirm-password');
        let companyCheckbox = $('#company');
        let userNamePattern = /^[A-Za-z0-9]{3,20}$/;
        let passwordPattern = /^[A-Za-z0-9_]{5,15}$/;
        let companyNumberPattern = /^[1-9][0-9]{3}$/;
        let emailPattern = /^[a-zA-Z0-9]+\@[a-z]+\.[a-z]+$/;

        let submit = $('#submit');

        companyCheckbox.on('click', function (event) {
            if ((companyCheckbox).is(":checked")) {
                $('#companyInfo').css('display', 'block');
            }
            else {
                $('#companyInfo').css('display', 'none');
            }
        });

        submit.on('click', function (event) {
            event.preventDefault();

            let validName = isValidUsername(userName, userNamePattern);
            let validPass = isValidPassword(password, confPass, passwordPattern);
            let validEmail = isValidEmail(email,emailPattern);

            if (companyCheckbox.is(":checked")) {
                let validCompanyNum=isValidCompanyNum(companyNumberPattern);
                if(validCompanyNum && validEmail && validName && validPass) {
                    let valid = $('#valid');
                    valid.css('display', 'block')
                }
                return;
            }

            if (validEmail && validName && validPass) {
                let valid = $('#valid');
                valid.css('display', 'block')
            }
        })
    }

    function isValidEmail(email, emailPattern) {
        let isValidEmail = true;
        if (!email.val().match(emailPattern)) {
            email.css('border', '2px solid red');
            isValidEmail = false;
            return isValidEmail;
        }
        return isValidEmail;

    }

    function isValidCompanyNum(companyNumberPattern) {
        let isValid=true;
        let companyNumber = $('#companyNumber');
        if (!companyNumber.val().match(companyNumberPattern)) {
            companyNumber.css('border','2px solid red');
            isValid=false;
        }
        return isValid;
    }

    function isValidUsername(userName, userNamePattern) {
        let isValidUser=true;
        if (!userName.val().match(userNamePattern)) {
            userName.css('border','2px solid red');
            isValidUser = false;
        }
        return isValidUser;
    }

    function isValidPassword(password, confPass, passwordPattern) {
        let isValidPassword=true;
        let passwordVal = password.val();
        let confirmPassVal = confPass.val();

        if (passwordVal !== confirmPassVal
            || !passwordVal.match(passwordPattern)
            || !confirmPassVal.match(passwordPattern)) {
            password.css('border', '2px solid red');
            confPass.css('border', '2px solid red');
            isValidPassword = false;
        }
        return isValidPassword;

}