RFC / WIP - html_attributes function

extra/html-extra/HtmlAttributes.php

@@ -0,0 +1,221 @@
+<?php
+
+namespace Twig\Extra\Html;
+
+use Twig\Error\RuntimeError;
+
+final class HtmlAttributes
+{
+    /**
+     * Merges multiple attribute group arrays into a single array.
+     *
+     * `HtmlAttributes::merge(['id' => 'a', 'disabled' => true], ['hidden' => true])` becomes
+     * `['id' => 'a', 'disabled' => true, 'hidden' => true]`
+     *
+     * attributes override each other in the order they are provided.
+     *
+     * `HtmlAttributes::merge(['id' => 'a'], ['id' => 'b'])` becomes `['id' => 'b']`.
+     *
+     * However, `class` and `style` attributes are merged into an array so they can be concatenated in later processing.
+     *
+     * `HtmlAttributes::merge(['class' => 'a'], ['class' => 'b'], ['class' => 'c'])` becomes
+     * `['class' => ['a' => true, 'b' => true, 'c' => true]]`.
+     *
+     * style attributes are also merged into an array so they can be concatenated in later processing.
+     *
+     * `HtmlAttributes::merge(['style' => 'color: red'], ['style' => ['background-color' => 'blue']])` becomes
+     * `['style' => ['color: red;' => true, 'background-color: blue;' => true]]`.
+     *
+     * style attributes which are arrays with false and null values are also processed
+     *
+     * `HtmlAttributes::merge(['style' => ['color: red' => true]], ['style' => ['display: block' => false]]) becomes
+     * `['style' => ['color: red;' => true, 'display: block;' => false]]`.
+     *
+     * attributes can be provided as an array of key, value where the value can be true, false or null.
+     *
+     * Example:
+     * `HtmlAttributes::merge(['class' => ['a' => true, 'b' => false], ['class' => ['c' => null']])` becomes
+     * `['class' => ['a' => true, 'b' => false, 'c' => null]]`.
+     *
+     * `aria` and `data` arrays are expanded into `aria-*` and `data-*` attributes before further processing.
+     *
+     * Example:
+     *
+     * `HtmlAttributes::merge([data' => ['count' => '1']])` becomes `['data-count' => '1']`.
+     * `HtmlAttributes::merge(['aria' => ['hidden' => true]])` becomes `['aria-hidden' => true]`.
+     *
+     * @param ...$attributeGroup
+     * @return array
+     * @throws RuntimeError
+     * @see ./Tests/HtmlAttributesTest.php for usage examples
+     *
+     */
+    public static function merge(...$attributeGroup): array
+    {
+        $result = [];
+
+        $attributeGroupCount = 0;
+
+        foreach ($attributeGroup as $attributes) {
+
+            $attributeGroupCount++;
+
+            // Skip empty attributes
+            // Return early if no attributes are provided
+            // This could be false or null when using the twig ternary operator
+            if (!$attributes) {
+                continue;
+            }
+
+            if (!is_iterable($attributes)) {
+                throw new RuntimeError(sprintf('"%s" only works with mappings or "Traversable", got "%s" for argument %d.', self::class, \gettype($attributes), $attributeGroupCount));
+            }
+
+            // Alternative to is_iterable check above, cast the attributes to an array
+            // This would produce weird results but would not throw an error
+//            $attributes = (array)$attributes;
+
+            // data and aria arrays are expanded into data-* and aria-* attributes
+            $expanded = [];
+            foreach ($attributes as $key => $value) {
+                if (in_array($key, ['data', 'aria'])) {
+                    $value = (array)$value;
+                    foreach ($value as $k => $v) {
+                        $k = $key . '-' . $k;
+                        $expanded[$k] = $v;
+                    }
+                    continue;
+                }
+                $expanded[$key] = $value;
+            }
+
+            // Reset the attributes array to the flattened version
+            $attributes = $expanded;
+
+            foreach ($attributes as $key => $value) {
+
+                // Treat class and data-controller attributes as arrays
+                if (in_array($key, [
+                    'class',
+                    'data-controller',
+                    'data-action',
+                    'data-targets',
+                ])) {
+                    if (!array_key_exists($key, $result)) {
+                        $result[$key] = [];
+                    }
+                    $value = (array)$value;
+                    foreach ($value as $k => $v) {
+                        if (is_int($k)) {
+                            $classes = explode(' ', $v);
+                            foreach ($classes as $class) {
+                                $result[$key][$class] = true;
+                            }
+                        } else {
+                            $classes = explode(' ', $k);
+                            foreach ($classes as $class) {
+                                $result[$key][$class] = $v;
+                            }
+                        }
+                    }
+                    continue;
+                }
+
+                if ($key === 'style') {
+                    if (!array_key_exists('style', $result)) {
+                        $result['style'] = [];
+                    }
+                    $value = (array)$value;
+                    foreach ($value as $k => $v) {
+                        if (is_int($k)) {
+                            $styles = array_filter(explode(';', $v));
+                            foreach ($styles as $style) {
+                                $style = explode(':', $style);
+                                $sKey = trim($style[0]);
+                                $sValue = trim($style[1]);
+                                $result['style']["$sKey: $sValue;"] = true;
+                            }
+                        } elseif (is_bool($v) || is_null($v)) {
+                            $styles = array_filter(explode(';', $k));
+                            foreach ($styles as $style) {
+                                $style = explode(':', $style);
+                                $sKey = trim($style[0]);
+                                $sValue = trim($style[1]);
+                                $result['style']["$sKey: $sValue;"] = $v;
+                            }
+                        } else {
+                            $sKey = trim($k);
+                            $sValue = trim($v);
+                            $result['style']["$sKey: $sValue;"] = true;
+                        }
+                    }
+                    continue;
+                }
+
+                $result[$key] = $value;
+            }
+        }
+
+        return $result;
+    }
+
+    public static function renderAttributes($attributes): string
+    {
+        $return = [];
+
+        foreach ($attributes as $key => $value) {
+
+            // Skip null values regardless of attribute key
+            if ($value === null) {
+                continue;
+            }
+
+            // Handle class, style, data-controller value coercion
+            // array[] -> concatenate string
+            if (in_array($key, ['class', 'style', 'data-controller'])) {
+                $value = array_filter($value);
+                $value = array_keys($value);
+                $value = implode(' ', $value);
+            }
+
+            // Handle aria-* value coercion
+            // true -> 'true'
+            // false -> 'false,
+            // array[] ->  concatenate string
+            if (str_starts_with($key, 'aria-')) {
+                if ($value === true) {
+                    $value = 'true';
+                } elseif ($value === false) {
+                    $value = 'false';
+                } elseif(is_array($value)) {
+                    $value = join(" ", array_filter($value));
+                }
+
+            }
+
+            // Handle data-* value coercion
+            // array[] -> json
+            if (str_starts_with($key, 'data-')) {
+                if(is_array($value)) {
+                    $value = json_encode($value);
+                }
+            }
+
+            // Skip false values
+            if ($value === false) {
+                continue;
+            }
+
+            // Boolean attribute doesn't have a value
+             if ($value === true) {
+                $return[] = $key;
+                continue;
+            }
+
+            // Everything else gets added as an encoded value
+            $return[] = $key . '="' . htmlspecialchars($value) . '"';
+        }
+
+        return implode(' ', $return);
+    }
+}