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Static closure

Static closure is a targeted merge strategy for one entry point.

{
  label: 'admin route closure',
  type: 'static-closure',
  entryPoint: 'src/app/admin/admin.routes.ts',
}

It resolves the configured source entry point to the emitted esbuild output chunk, follows that chunk's static imports, and merges the entry point chunk with its unassigned static dependency closure.

What it does​

Static closure walks only import-statement edges from the selected entry point. It does not cross dynamic import boundaries.

For example, if admin.routes.ts statically imports an admin shell component, a table component, and a local utility chunk, those chunks can be grouped with the admin route entry chunk. If the admin route dynamically imports a nested detail route, that nested dynamic entry point is not pulled into the static closure.

Configuration​

esbuild.plugins.ts
import optimizeChunksPlugin from '@rx-angular/rebundle';
import type { MergeStrategyConfig } from '@rx-angular/rebundle';

const mergeStrategy: MergeStrategyConfig = {
  name: 'targeted-routes',
  strategies: [
    {
      label: 'admin route closure',
      type: 'static-closure',
      entryPoint: 'src/app/admin/admin.routes.ts',
    },
  ],
};

export default optimizeChunksPlugin({ mergeStrategy });

The entryPoint value is the source entry point path from the esbuild metafile. It is not the emitted chunk filename.

Behavior​

  • entryPoint must resolve to an esbuild output whose metadata has a matching entryPoint value.
  • The strategy includes the entry point output chunk in the merge group.
  • The strategy follows only static imports.
  • Dynamic imports remain separate entry points.
  • Chunks already assigned by earlier strategies are skipped.
  • The resulting merge group is keyed by the emitted output chunk for the configured entry point.

Use static closure when a specific lazy route or feature entry point should load as a more cohesive bundle.

Good fits include:

  • A route where the first screen immediately needs most of its statically imported dependencies.
  • A feature whose generated output has too many small chunks.
  • A feature where a slightly larger route chunk is preferable to a burst of small requests.

Avoid applying static closure broadly to every lazy route by default. It is a manual policy and should describe a specific loading decision.

Ordering​

Static closure respects previous assignments. If an earlier strategy already assigned a dependency, static closure leaves that dependency alone.

For targeted configs, put more specific rules before broader rules. For example, create a custom common group first, then use static closure for the remaining feature-specific dependencies.