Email validation using JavaScript failing at if statment

Question

As part of a Frontend Mentor challenge, I am creating a simple email validation for a subscription landing page. It simply checks whether the email field is empty, if so, it throws an error message. Another error message is shown if the user enters an incorrect email address.

I've created a function called checkInputs() which contains a conditional else if statement

When testing on live server, the first condition works fine, when I leave the email field empty, however, the second condition doesn't even run, nor does the third.

I've included the full in case it's anything else throwing the whole function off. I tested the function isEmail() which checks whether the email is valid, and it works fine for me.

const form = document.getElementById('form');
const email = document.getElementById('email');

form.addEventListener('submit', (e) => {
  e.preventDefault();
  checkInputs();
})

function checkInputs() {
  const emailValue = email.value;
  const emptyEmail = emailValue === '';
  const invalidEmail = !isEmail(emailValue);

  if (emptyEmail) {
    setErrorFor(email, 'Oops! Please add your email');
  } else if (invalidEmail) {
    setErrorFor(email, 'Oops! Please check your email');
  } else {
    setSuccessFor(emailValue);
  }
};

function setErrorFor(input, message) {
  const formGroup = input.parentElement;
  const small = formGroup.querySelector('small');
  formGroup.className = 'form-group error';
  small.innerHTML = message;
}

function setSuccessFor(input) {
  const formGroup = input.parentElement;
  formGroup.className = 'form-group success';
}

// checks if email is valid
function isEmail(email) {
  const regx = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;

  return regx.test(email);
}

<div class="form-group">
  <form id="form" method="POST" name="subscribe">
    <input type="email" placeholder="Email address" name="email" id="email" class="email-input error">
    <br>
    <small></small>
    <br>
    <button class="form-btn" type="submit">Request Access</button>
  </form>
</div>

Answer 1

Console says:

Uncaught TypeError: Cannot set properties of undefined (setting 'className')

on

function setSuccessFor(input) {
  const formGroup = input.parentElement;
  formGroup.className = 'form-group success';
}

You are not passing a form element

1. Change setSuccessFor(email);
2. I advise to also change formGroup.classList.add('success');
3. Perhaps remove the success before testing, although it is currently not possible to add a wrong email due the the HTML5 validation

const form = document.getElementById('form');
const email = document.getElementById('email');

form.addEventListener('submit', (e) => {
  e.preventDefault();
  checkInputs();
})

function checkInputs() {
  const emailValue = email.value;
  const emptyEmail = emailValue === '';
  const invalidEmail = !isEmail(emailValue);
  email.parentElement.classList.remove('success');
  if (emptyEmail) {
    setErrorFor(email, 'Oops! Please add your email');
  } else if (invalidEmail) {
    setErrorFor(email, 'Oops! Please check your email');
  } else {
    setSuccessFor(email);
  }
};

function setErrorFor(input, message) {
  const formGroup = input.parentElement;
  const small = formGroup.querySelector('small');
  formGroup.className = 'form-group error';
  small.innerHTML = message;
}

function setSuccessFor(input) {
  const formGroup = input.parentElement;
  formGroup.classList.add('success');
}

// checks if email is valid
function isEmail(email) {
  const regx = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;

  return regx.test(email);
}

.success { background-color:green }

<div class="form-group">
  <form id="form" method="POST" name="subscribe">
    <input type="email" placeholder="Email address" name="email" id="email" class="email-input error">
    <br>
    <small></small>
    <br>
    <button class="form-btn" type="submit">Request Access</button>
  </form>
</div>