Pages Aggregator

A PagesAggregator generates additional routes after all pages are loaded. Unlike route loaders, aggregators don't load pages from a source — they analyze the already-loaded pages and produce routes based on their content or metadata.

This is useful for any case where the set of routes depends on the content of your pages, such as tag pages, category archives, or any other derived view.

How It Works

Aggregators run after all RouteLoaders have finished loading content pages. Each aggregator receives the full list of loaded content pages and returns a list of Routes to add to the router.

ContentApp.custom(
  eagerlyLoadAllPages: true,
  loaders: [FilesystemLoader('content')],
  pagesAggregators: [
    MyAggregator(),
  ],
  configResolver: PageConfig.all(/* ... */),
);

Route Info

Alongside routes, aggregators can produce AggregatedRouteInfo objects that carry metadata for each generated route. These are accessible from within a route builder via context.currentRouteInfo<T>():

final info = context.currentRouteInfo<MyRouteInfo>();

This lets you pass structured data from the aggregator to the route builder without relying on closures or global state.

Built-in Aggregator: TaxonomyAggregator

jaspr_content ships with a built-in aggregator for taxonomy use cases — TaxonomyAggregator. It scans page frontmatter for a given field (e.g., tags) and generates routes for each unique value (term):

TaxonomyAggregator(
  taxonomy: 'tags',
  termPageBuilder: (context, taxonomy, term) => TagPage(term: term),
  taxonomyPageBuilder: (context, taxonomy) => TagsPage(),
)

See the Taxonomy page for details.

Custom Aggregators

To create a custom aggregator, extend PagesAggregator and implement aggregatePages:

class ArchiveAggregator extends PagesAggregator {
  @override
  Future<List<Route>> aggregatePages(
    List<Page> pages,
    List<AggregatedRouteInfo> routeInfos,
  ) async {
    // Group pages by year based on a 'date' frontmatter field.
    final byYear = <int, List<Page>>{};
    for (final page in pages) {
      final date = page.data.page['date'];
      if (date is String) {
        final year = DateTime.parse(date).year;
        byYear.putIfAbsent(year, () => []).add(page);
      }
    }

    return [
      for (final entry in byYear.entries)
        Route(
          path: '/archive/${entry.key}',
          builder: (context, _) => ArchivePage(year: entry.key, pages: entry.value),
        ),
    ];
  }
}