build: name the lazy Navara engine chunk navara-engine

chunkFileNames names the chunk holding src/globe/navara
navara-engine-[hash].js; chunking is unchanged (manualChunks would pull
modules shared with the Cesium entry into it and make the entry import
it). The Cesium main chunk stays 2,849,217 B.

build/navaraAssets.js

@@ -43,3 +43,23 @@ export function navaraWorkerAssets({ assetsDir } = {}) {
     },
   };
 }
+
+const NAVARA_MODULE = /\/src\/globe\/navara\//;
+
+/**
+ * Rollup chunkFileNames: the lazy chunk holding the Navara engine
+ * (src/globe/navara, with the Navara packages it pulls in) is named
+ * `navara-engine-[hash].js`; every other chunk keeps Vite's default name.
+ * Naming only (not manualChunks, which would pull modules shared with the
+ * Cesium entry into the Navara chunk), so the chunking is unchanged.
+ * @param {{ isEntry?: boolean, moduleIds?: string[] }} chunk
+ * @returns {string}
+ */
+export function navaraChunkFileNames(chunk) {
+  const navara =
+    !chunk.isEntry &&
+    (chunk.moduleIds ?? []).some((id) =>
+      NAVARA_MODULE.test(id.replaceAll('\\', '/')),
+    );
+  return navara ? 'assets/navara-engine-[hash].js' : 'assets/[name]-[hash].js';
+}

build/vite.js

@@ -3,7 +3,7 @@ import cesium from 'vite-plugin-cesium';
 import { DEFAULT_ALLOWED_HOSTS, hostCheckPlugin } from './allowedHosts.js';
 import { embedFramingPlugin } from './embed-framing.js';
 import { panelBuildPlugin } from './panel.js';
-import { navaraWorkerAssets } from './navaraAssets.js';
+import { navaraChunkFileNames, navaraWorkerAssets } from './navaraAssets.js';
 
 /**
  * Content-Security-Policy for every document the dev/preview server serves.
@@ -130,7 +130,11 @@ export function createBrowserViteConfig({
       chunkSizeWarningLimit: 1500,
       // Build only: the wasm Navara's workers load by name (the Navara
       // engine is a separate chunk loaded on ?engine=navara).
-      rollupOptions: { plugins: [navaraWorkerAssets()] },
+      // The lazy chunk with the Navara engine is named navara-engine.
+      rollupOptions: {
+        plugins: [navaraWorkerAssets()],
+        output: { chunkFileNames: navaraChunkFileNames },
+      },
     },
   };
 }

src/tooling/navaraAssets.test.mjs

@@ -54,3 +54,33 @@ test('the browser build runs the Navara asset copy as a Rollup plugin', () => {
   );
   assert.equal(build.chunkSizeWarningLimit, 1500);
 });
+
+test('the lazy chunk with the Navara engine is named navara-engine', async () => {
+  const { navaraChunkFileNames } = await import('../../build/navaraAssets.js');
+  for (const ids of [
+    ['/repo/src/globe/navara/index.js', '/repo/src/globe/navara/maps.js'],
+    [
+      '/repo/node_modules/@navaramap/three/dist/index.js',
+      '/repo/src/globe/navara/index.js',
+    ],
+  ])
+    assert.equal(
+      navaraChunkFileNames({ isEntry: false, moduleIds: ids }),
+      'assets/navara-engine-[hash].js',
+    );
+  for (const chunk of [
+    { isEntry: false, moduleIds: ['/repo/src/app/navaraMode.js'] },
+    { isEntry: false, moduleIds: ['/repo/src/globe/contract.js'] },
+    // A package chunk split off by the bundler keeps its own name.
+    {
+      isEntry: false,
+      moduleIds: ['/repo/node_modules/@navaramap/three/dist/spark.js'],
+    },
+    { isEntry: true, moduleIds: ['/repo/src/globe/navara/index.js'] },
+    { isEntry: false },
+  ])
+    assert.equal(navaraChunkFileNames(chunk), 'assets/[name]-[hash].js');
+  const { build } = createBrowserViteConfig({});
+  assert.equal(build.rollupOptions.output.chunkFileNames, navaraChunkFileNames);
+  assert.equal(build.rollupOptions.output.manualChunks, undefined);
+});