added html_attr function to the HtmlExtension extension

CHANGELOG

@@ -1,6 +1,7 @@
 * 2.12.3 (2019-XX-XX)
 
- * fixed number formatter in Intl extra extension when using a formatter prototype
+* fixed number formatter in Intl extra extension when using a formatter prototype
+* added "html_attr" function to the HtmlExtension extension in the "extra" repositories
 
 * 2.12.2 (2019-11-11)
 

doc/functions/html_attr.rst

@@ -0,0 +1,37 @@
+``html_attr``
+================
+
+.. versionadded:: 2.x
+    The ``html_attr`` function was added in Twig 2.x.
+
+The ``html_attr`` function returns a string by joining html attributes together:
+
+.. code-block:: twig
+
+    {% set attr = {
+            id: 123,
+            disabled: true,
+            hidden: false,
+            type: 'button',
+            'aria-expandend': 'false',
+        } %}
+    <button{{ html_attr(attr) }}></button>
+
+    {# example output: <button id="123" disabled type="button" aria-expandend="false"></button> #}
+
+.. note::
+
+    The ``html_attr`` function is part of the ``HtmlExtension`` which is not
+    installed by default. Install it first:
+
+    .. code-block:: bash
+
+        $ composer req twig/html-extra
+
+    Then, use the ``twig/extra-bundle`` on Symfony projects or add the extension
+    explictly on the Twig environment::
+
+        use Twig\Extra\Html\HtmlExtension;
+
+        $twig = new \Twig\Environment(...);
+        $twig->addExtension(new HtmlExtension());

extra/html-extra/src/HtmlExtension.php

@@ -35,6 +35,7 @@ public function getFunctions()
     {
         return [
             new TwigFunction('html_classes', 'twig_html_classes'),
+            new TwigFunction('html_attr', 'twig_html_attributes', ['needs_environment' => true, 'is_safe' => ['html']]),
         ];
     }
 
@@ -83,6 +84,7 @@ public function dataUri(string $data, string $mime = null, array $parameters = [
 }
 
 namespace {
+use Twig\Environment;
 use Twig\Error\RuntimeError;
 
 function twig_html_classes(...$args): string
@@ -108,4 +110,24 @@ function twig_html_classes(...$args): string
 
     return implode(' ', array_unique($classes));
 }
+
+function twig_html_attributes(Environment $env, array $attributes): string
+{
+    $output = '';
+
+    foreach ($attributes as $attribute => $value) {
+        $attribute = \htmlspecialchars($attribute, ENT_COMPAT | ENT_HTML5, $env->getCharset(), false);
+
+        if ($value === true) {
+            $output .= ' ' . $attribute;
+        } else if (\is_string($value) || \is_numeric($value)) {
+            $value = \htmlspecialchars($value, ENT_COMPAT | ENT_HTML5, $env->getCharset(), false);
+            $output .= sprintf(' %s="%s"', $attribute, $value);
+        } else if ($value !== false) {
+            throw new RuntimeError(sprintf('The html_attr function argument value of key %d should be either a boolean, string or number, got "%s".', $attribute, \gettype($value)));
+        }
+    }
+
+    return $output;
+}
 }

extra/html-extra/tests/Fixtures/html_attr.test

@@ -0,0 +1,15 @@
+--TEST--
+"html_attr" function
+--TEMPLATE--
+{% set attr = {
+        'aria-expandend': 'false',
+        disabled: true,
+        hidden: false,
+        id: 123,
+        title: 'cli"<ck',
+    } %}
+{{ html_attr(attr) }}
+--DATA--
+return []
+--EXPECT--
+ aria-expandend="false" disabled id="123" title="cli&quot;&lt;ck"

extra/html-extra/tests/Fixtures/html_attr_with_unsupported_key.test

@@ -0,0 +1,8 @@
+--TEST--
+"html_attr" function
+--TEMPLATE--
+{{ html_attr({ test: { foo: 'bar' }}) }}
+--DATA--
+return []
+--EXCEPTION--
+Twig\Error\RuntimeError: The html_attr function argument value of key 0 should be either a boolean, string or number, got "array" in "index.twig" at line 2.