Wordpress Gravity form custom Validation - wordpress

Question

I created a form with gravity forms in Wordpress, But I'm trying to create a custom validation with an auto text field I create, So unless the user pick one of the option I put in the form, it should give an error.
I found this example on the gravity forms website, so this form give you an error if you enter a lower case "One and Two".
add_filter( 'gform_field_validation_6_3', function ( $result, $value, $form, $field ) {
GFCommon::log_debug( __METHOD__ . '(): Running...' );
// Only for Single Line Text and Paragraph fields.
if ( $field->type == 'text' || $field->type == 'textarea' ) {
if ( $result['is_valid'] ) {
$stop_words = array( // List of words to not allow in lowercase.
'one',
'two',
);
if ( in_array( strtolower( $value ), $stop_words ) ) {
GFCommon::log_debug( __METHOD__ . '(): Stop word detected: ' . $value );
$result['is_valid'] = false;
$result['message'] = 'Sorry, you used a not allowed word.';
}
}
}
return $result;
}, 10, 4 );
I want to reverse it so that unless you put these specific words " one, two " you get an error

Answer 1

You can add an exclamation point before the in_array() function which will make it stop any value not found in the array:
add_filter( 'gform_field_validation_6_3', function ( $result, $value, $form, $field ) {
GFCommon::log_debug( __METHOD__ . '(): Running...' );
// Only for Single Line Text and Paragraph fields.
if ( $field->type == 'text' || $field->type == 'textarea' ) {
if ( $result['is_valid'] ) {
$stop_words = array( // List of words to not allow in lowercase.
'one',
'two',
);
if ( !in_array( strtolower( $value ), $stop_words ) ) {
GFCommon::log_debug( __METHOD__ . '(): Stop word detected: ' . $value );
$result['is_valid'] = false;
$result['message'] = 'Sorry, you used a not allowed word.';
}
}
}
return $result;
}, 10, 4 );