[5.x] Attribute Modifier (#9796)

Co-authored-by: Duncan McClean <[email protected]>
Co-authored-by: Jason Varga <[email protected]>

src/Modifiers/CoreModifiers.php

@@ -157,6 +157,48 @@ public function at($value, $params)
  return Stringy::at($value, Arr::get($params, 0));
  }
 
+ /**
+ * Returns an attribute ($params[0]) with its value when the given $value variable is not empty.
+ *
+ * @param string $value
+ * @param array $params
+ * @return string
+ */
+ public function attribute($value, $params)
+ {
+ if (! $name = Arr::get($params, 0)) {
+ throw new \Exception('Attribute name is required.');
+ }
+
+ if ($value instanceof Collection) {
+ $value = $value->all();
+ }
+
+ if (\is_array($value)) {
+ if (empty($value)) {
+ return '';
+ }
+
+ $value = \json_encode($value);
+ }
+
+ if (\is_bool($value)) {
+ return $value ? ' '.$name : '';
+ }
+
+ if (\is_object($value)) {
+ $value = (string) $value;
+ }
+
+ $value = trim($value);
+
+ if ($value === '') {
+ return '';
+ }
+
+ return sprintf(' %s="%s"', $name, Html::entities($value));
+ }
+
  /**
  * Returns a focal point as a background-position CSS value.
  *

tests/Modifiers/AttributeTest.php

@@ -0,0 +1,74 @@
+<?php
+
+namespace Tests\Modifiers;
+
+use Statamic\Modifiers\Modify;
+use Tests\TestCase;
+
+class AttributeTest extends TestCase
+{
+ /**
+ * @test
+ *
+ * @dataProvider attributeProvider
+ */
+ public function it_converts_to_attribute($value, $expected)
+ {
+ $this->assertEquals($expected, $this->modify($value, 'foo'));
+ }
+
+ public static function attributeProvider()
+ {
+ return [
+ 'string' => ['bar baz', ' foo="bar baz"'],
+ 'entities' => ['{<!&>}', ' foo="{&lt;!&amp;&gt;}"'],
+ 'integer' => [1, ' foo="1"'],
+ 'integer > 1' => [2, ' foo="2"'],
+ 'negative integer' => [-1, ' foo="-1"'],
+ 'float' => [1.5, ' foo="1.5"'],
+ 'empty string' => ['', ''],
+ 'true' => [true, ' foo'],
+ 'false' => [false, ''],
+ 'array' => [['one' => ['two' => 'three']], ' foo="{&quot;one&quot;:{&quot;two&quot;:&quot;three&quot;}}"'],
+ 'empty array' => [[], ''],
+ 'collection' => [collect(['one' => 'two']), ' foo="{&quot;one&quot;:&quot;two&quot;}"'],
+ 'empty collection' => [collect(), ''],
+ 'object with __toString' => [new AttributeTestStringable, ' foo="Test"'],
+ ];
+ }
+
+ /** @test */
+ public function it_throws_exception_without_argument()
+ {
+ $this->expectException(\Exception::class);
+ $this->expectExceptionMessage('Attribute name is required.');
+
+ $this->modify('value', null);
+ }
+
+ /** @test */
+ public function it_throws_exception_when_value_is_an_object_without_toString_method()
+ {
+ $this->expectException(\Error::class);
+ $this->expectExceptionMessage('Object of class Tests\Modifiers\AttributeTestNotStringable could not be converted to string');
+
+ $this->modify(new AttributeTestNotStringable, 'foo');
+ }
+
+ private function modify($value, $attribute)
+ {
+ return Modify::value($value)->attribute($attribute)->fetch();
+ }
+}
+
+class AttributeTestStringable
+{
+ public function __toString()
+ {
+ return 'Test';
+ }
+}
+
+class AttributeTestNotStringable
+{
+}