SelectBox: prompt <option> is hidden

- only makes sense for the required element
- workaround for Safari: disabled & selected attributes

Author: dg

src/Forms/Controls/SelectBox.php

@@ -96,17 +96,22 @@ public function getControl(): Nette\Utils\Html
 		}
 
 		$attrs = $this->optionAttributes;
-		$attrs['disabled:'] = is_array($this->disabled) ? $this->disabled : null;
+		$attrs['disabled:'] = is_array($this->disabled) ? $this->disabled : [];
 
+		$selected = $this->value;
 		if ($this->prompt !== false) {
 			$promptKey = '';
 			while (isset($items[$promptKey])) {
 				$promptKey .= "\x1";
 			}
 			$items = [$promptKey => $this->translate($this->prompt)] + $items;
+			if ($this->isRequired()) {
+				$attrs['hidden:'][$promptKey] = $attrs['disabled:'][$promptKey] = true;
+				$selected ??= $promptKey; // disabled & selected for Safari, hidden for other browsers
+			}
 		}
 
-		return Nette\Forms\Helpers::createSelectBox($items, $attrs, $this->value)
+		return Nette\Forms\Helpers::createSelectBox($items, $attrs, $selected)
 			->addAttributes(parent::getControl()->attrs);
 	}
 

tests/Forms/Controls.SelectBox.render.phpt

@@ -61,6 +61,36 @@ test('selected 2x', function () {
 });
 
 
+test('prompt', function () {
+	$form = new Form;
+	$input = $form->addSelect('list', 'Label', [
+		'a' => 'First',
+		0 => 'Second',
+	])->setPrompt('prompt');
+
+	Assert::same('<select name="list" id="frm-list"><option value="">prompt</option><option value="a">First</option><option value="0">Second</option></select>', (string) $input->getControl());
+
+	$input->setValue(0);
+
+	Assert::same('<select name="list" id="frm-list"><option value="">prompt</option><option value="a">First</option><option value="0" selected>Second</option></select>', (string) $input->getControl());
+});
+
+
+test('prompt + required', function () {
+	$form = new Form;
+	$input = $form->addSelect('list', 'Label', [
+		'a' => 'First',
+		0 => 'Second',
+	])->setPrompt('prompt')->setRequired();
+
+	Assert::same('<select name="list" id="frm-list" required data-nette-rules=\'[{"op":":filled","msg":"This field is required."}]\'><option value="" disabled hidden selected>prompt</option><option value="a">First</option><option value="0">Second</option></select>', (string) $input->getControl());
+
+	$input->setValue(0);
+
+	Assert::same('<select name="list" id="frm-list" required data-nette-rules=\'[{"op":":filled","msg":"This field is required."}]\'><option value="" disabled hidden>prompt</option><option value="a">First</option><option value="0" selected>Second</option></select>', (string) $input->getControl());
+});
+
+
 test('unique prompt', function () {
 	$form = new Form;
 	$input = $form->addSelect('list', 'Label', [