What are the potential pitfalls of using empty() function to check for empty strings in PHP?

Using the empty() function to check for empty strings in PHP can lead to unexpected results because empty() considers a string containing only whitespace characters as empty. To accurately check for an empty string, it's better to use the strict comparison operator (===) with an empty string (''). This ensures that only strings with no characters at all are considered empty.

// Incorrect usage of empty() function
$string = "   ";
if (empty($string)) {
    echo "String is empty";
} else {
    echo "String is not empty";
}

// Correct way to check for empty string
if ($string === '') {
    echo "String is empty";
} else {
    echo "String is not empty";
}