islandRuntime function

List<DocumentNode> islandRuntime({ String engineScript = '/flutter_bootstrap.js', String? islandElementIntegrity, String? dispatcherIntegrity, })

Returns the runtime script nodes needed for island hydration: the engine bootstrap location via HYDRALINE_CONFIG, the custom element, and the dispatcher. engineScript points to the Flutter engine bootstrap (defaults to /flutter_bootstrap.js).

islandElementIntegrity and dispatcherIntegrity are optional Subresource Integrity (SRI) hashes (sha384-...) for the shipped hydraline-island.js and hydraline-dispatcher.js assets. When supplied, the <script> tags carry integrity and crossorigin="anonymous" attributes, guaranteeing the browser rejects a tampered runtime even when the CDN or static host is compromised.

The returned nodes are UnsafeHtmlNode instances carrying trusted, static <script> markup - no user-input interpolation.

Implementation

List<DocumentNode> islandRuntime({
  String engineScript = '/flutter_bootstrap.js',
  String? islandElementIntegrity,
  String? dispatcherIntegrity,
}) {
  final islandAttrs = islandElementIntegrity != null
      ? ' integrity="$islandElementIntegrity" crossorigin="anonymous"'
      : '';
  final dispatcherAttrs = dispatcherIntegrity != null
      ? ' integrity="$dispatcherIntegrity" crossorigin="anonymous"'
      : '';

  return [
    UnsafeHtmlNode(
      '<script>'
      "window.HYDRALINE_CONFIG={engineScript:'$engineScript'}"
      '</script>'
      '<script src="/hydraline-island.js" defer$islandAttrs></script>'
      '<script src="/hydraline-dispatcher.js" defer$dispatcherAttrs></script>',
    ),
  ];
}