init with kirby, vue and pagedjs interactive

public/kirby/src/Content/VersionId.php

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+<?php
+
+namespace Kirby\Content;
+
+use Closure;
+use Kirby\Exception\InvalidArgumentException;
+use Stringable;
+
+/**
+ * The Version ID identifies a version of content.
+ * This can be the currently latest version or changes
+ * to the content. In the future, we also plan to use this
+ * for older revisions of the content.
+ *
+ * @package   Kirby Content
+ * @author    Bastian Allgeier <bastian@getkirby.com>
+ * @link      https://getkirby.com
+ * @copyright Bastian Allgeier
+ * @license   https://getkirby.com/license
+ * @since     5.0.0
+ * @unstable
+ */
+class VersionId implements Stringable
+{
+	/**
+	 * Latest stable version of the content
+	 */
+	public const LATEST = 'latest';
+
+	/**
+	 * Latest changes to the content (optional)
+	 */
+	public const CHANGES = 'changes';
+
+	/**
+	 * A global store for a version id that should be
+	 * rendered for each model in a live preview scenario.
+	 */
+	public static self|null $render = null;
+
+	/**
+	 * @throws \Kirby\Exception\InvalidArgumentException If the version ID is not valid
+	 */
+	public function __construct(
+		public string $value
+	) {
+		if (in_array($value, [static::CHANGES, static::LATEST], true) === false) {
+			throw new InvalidArgumentException(message: 'Invalid Version ID');
+		}
+	}
+
+	/**
+	 * Converts the VersionId instance to a simple string value
+	 */
+	public function __toString(): string
+	{
+		return $this->value;
+	}
+
+	/**
+	 * Creates a VersionId instance for the latest content changes
+	 */
+	public static function changes(): static
+	{
+		return new static(static::CHANGES);
+	}
+
+	/**
+	 * Creates a VersionId instance from a simple string value
+	 */
+	public static function from(VersionId|string $value): static
+	{
+		if ($value instanceof VersionId) {
+			return $value;
+		}
+
+		return new static($value);
+	}
+
+	/**
+	 * Compares a VersionId object or string value with this id
+	 */
+	public function is(VersionId|string $id): bool
+	{
+		return static::from($id)->value === $this->value;
+	}
+
+	/**
+	 * Creates a VersionId instance for the latest stable version of the content
+	 */
+	public static function latest(): static
+	{
+		return new static(static::LATEST);
+	}
+
+	/**
+	 * Temporarily sets the version ID for preview rendering
+	 * only for the logic in the callback
+	 */
+	public static function render(VersionId|string $versionId, Closure $callback): mixed
+	{
+		$original       = static::$render;
+		static::$render = static::from($versionId);
+
+		try {
+			return $callback();
+		} finally {
+			// ensure that the render version ID is *always* reset
+			// to the original value, even if an error occurred
+			static::$render = $original;
+		}
+	}
+
+	/**
+	 * Returns the ID value
+	 */
+	public function value(): string
+	{
+		return $this->value;
+	}
+}