How to make a 2nd check after first row of validations - php

Question

I have am trying to re-create a form register validation that I seen a few weeks ago but unable to figure it out.
I want to perform one last check after the first 3 checks then display the message
validation code
public function validateSignup(): bool
{
$this->errors = [];
if (empty($this->name) || (strlen($this->name) < 4)) {
$this->errors['name'] = "Username must be at least 4 characters.";
}
if (empty($this->email) || (filter_var($this->email, FILTER_VALIDATE_EMAIL) === false)) {
$this->errors['email'] = "Email address is required.";
}
if (empty($this->password) || strlen($this->password) < 6) {
$this->errors['password'] = "Password is required.";
}
return empty($this->errors);
}
This works great for the validation requirements but I want to add another step, to check if email or username is taken, I know how to do this traditionally but wanted to make it different without giving information away.
I have a Helper to tell me if an email is in the database called alreadyExists
what I am trying to accomplish is a 2nd check after that
Example
public function validateSignup(): bool
{
$this->errors = [];
if (empty($this->name) || (strlen($this->name) < 4)) {
$this->errors['name'] = "Username must be at least 4 characters.";
}
if (empty($this->email) || (filter_var($this->email, FILTER_VALIDATE_EMAIL) === false)) {
$this->errors['email'] = "Email address is required.";
}
if (empty($this->password) || strlen($this->password) < 6) {
$this->errors['password'] = "Password is required.";
}
return empty($this->errors);
## after it checks validation with no errors check if already exists
if ($this->name) Helpers::alreadyExists("user", "name", $this->name) {
$this->errors['name'] = "Unable to register user with provided data.";
}
return $this->errors;
}

Answer 1

public function validateSignup(): bool {
$this->errors = [];
if (empty($this->name) || (strlen($this->name) < 4)) {
$this->errors['name'] = "Username must be at least 4 characters.";
}
if (empty($this->email) || (filter_var($this->email, FILTER_VALIDATE_EMAIL) === false)) {
$this->errors['email'] = "Email address is required.";
}
if (empty($this->password) || strlen($this->password) < 6) {
$this->errors['password'] = "Password is required.";
}
If(count($this->errors) > 0) {
return empty($this->errors);
}
## after it checks validation with no errors check if already exists
if ($this->name) Helpers::alreadyExists("user", "name", $this->name) {
$this->errors['name'] = "Unable to register user with provided data.";
}
return empty($this->errors);
}