Reply To: Avoid duplicate content on repeater field

• tomgreeen

• April 30, 2021 at 3:52 am

Thanks for this suggestion @hube2 – this is a nice piece of functionality.

I made some tweaks for my use case, pasted here in case useful to anyone. In my case, I want to be able to check that the first field of each the repeater is unique – I don’t care what happens to the others. This way the field becomes a key.

NB this doesn’t currently work for nested repeaters-in-repeaters. One day I may try to tackle that.

The main function is here:

add_filter('acf/validate_value/type=repeater', 'grly_acf_validate_repeater', 10, 4);

function grly_acf_validate_repeater($valid, $value, $field, $input) {

	if (!$valid || !$field['preventduplicates']) {
		return $valid;
	}

	// get list of array indexes from $input
	// [ <= this fixes my IDE, it has problems with unmatched brackets
	preg_match_all('/\[([^\]]+)\]/', $input, $matches);
	if (!count($matches[1])) {
		// this should actually never happen
		return $valid;
	}
	$matches = $matches[1];

	// walk the acf input to find the repeater and current row
	$array = $_POST['acf'];

	$field_key = false;
	$field_value = false;

	for ($i = 0; $i < count($matches); $i++) {
		if (isset($array[$matches[$i]])) {

			$field_key = $matches[$i];
			$field_value = $array[$matches[$i]];

			if ($field_key == $field['key']) {
				break;
			}
			$array = $field_value;

		}
	}

	$used = [];
	foreach ($field_value as $index => $row) {
		$first_entry = reset($row); // Extracts the first entry in the object for that row;
		if ($first_entry) {
			if (!in_array($first_entry, $used)) {
				$used[] = $first_entry;
			} else {
				$valid = 'The value ' . $first_entry . ' is used more than once. The first field in this repeater must be unique across the repeater.';
				break;
			}
		}
	}

	return $valid;
}

… then I’ve added a ‘prevent duplicates’ field to all repeaters so that it can be toggled on and off:

add_action('acf/render_field_settings/type=repeater', 'add_no_duplicates_field_to_repeater');
function add_no_duplicates_field_to_repeater($field) {
	acf_render_field_setting($field, [
		'label' => __('Prevent duplicates?', 'acf'),
		'instructions' => 'Prevents rows being saved where the first value is the same as that in another row',
		'type' => 'radio',
		'name' => 'preventduplicates',
		'choices' => array(
			1 => __("Yes", 'acf'),
			0 => __("No", 'acf'),
		),
		'default_value' => 0,
		'layout' => 'horizontal',
	]);

}