perf(cli): enable code splitting and deferred UI loading (#22117)

scripts/build_binary.js

@@ -228,23 +228,35 @@ const packageJson = JSON.parse(
 // Helper to calc hash
 const sha256 = (content) => createHash('sha256').update(content).digest('hex');
 
-// Read Main Bundle
-const geminiBundlePath = join(root, 'bundle/gemini.js');
-const geminiContent = readFileSync(geminiBundlePath);
-const geminiHash = sha256(geminiContent);
-
 const assets = {
-  'gemini.mjs': geminiBundlePath, // Use .js source but map to .mjs for runtime ESM
   'manifest.json': 'bundle/manifest.json',
 };
 
 const manifest = {
   main: 'gemini.mjs',
-  mainHash: geminiHash,
+  mainHash: '',
   version: packageJson.version,
   files: [],
 };
 
+// Add all javascript chunks from the bundle directory
+const jsFiles = globSync('*.js', { cwd: bundleDir });
+for (const jsFile of jsFiles) {
+  const fsPath = join(bundleDir, jsFile);
+  const content = readFileSync(fsPath);
+  const hash = sha256(content);
+
+  // Node SEA requires the main entry point to be explicitly mapped
+  if (jsFile === 'gemini.js') {
+    assets['gemini.mjs'] = fsPath;
+    manifest.mainHash = hash;
+  } else {
+    // Other chunks need to be mapped exactly as they are named so dynamic imports find them
+    assets[jsFile] = fsPath;
+    manifest.files.push({ key: jsFile, path: jsFile, hash: hash });
+  }
+}
+
 // Helper to recursively find files from STAGING
 function addAssetsFromDir(baseDir, runtimePrefix) {
   const fullDir = join(stagingDir, baseDir);
@@ -346,6 +358,22 @@ const targetBinaryPath = join(targetDir, binaryName);
 console.log(`Copying node binary from ${nodeBinary} to ${targetBinaryPath}...`);
 copyFileSync(nodeBinary, targetBinaryPath);
 
+if (platform === 'darwin') {
+  console.log(`Thinning universal binary for ${arch}...`);
+  try {
+    // Attempt to thin the binary. Will fail safely if it's not a fat binary.
+    runCommand('lipo', [
+      targetBinaryPath,
+      '-thin',
+      arch,
+      '-output',
+      targetBinaryPath,
+    ]);
+  } catch (e) {
+    console.log(`Skipping lipo thinning: ${e.message}`);
+  }
+}
+
 // Remove existing signature using helper
 removeSignature(targetBinaryPath);
 
@@ -357,9 +385,7 @@ if (existsSync(bundleDir)) {
 
 // Clean up source JS files from output (we only want embedded)
 const filesToRemove = [
-  'gemini.js',
   'gemini.mjs',
-  'gemini.js.map',
   'gemini.mjs.map',
   'gemini-sea.cjs',
   'sea-launch.cjs',
@@ -373,6 +399,12 @@ filesToRemove.forEach((f) => {
   if (existsSync(p)) rmSync(p, { recursive: true, force: true });
 });
 
+// Remove all chunk and entry .js/.js.map files
+const jsFilesToRemove = globSync('*.{js,js.map}', { cwd: targetDir });
+for (const f of jsFilesToRemove) {
+  rmSync(join(targetDir, f));
+}
+
 // Remove .sb files from targetDir
 const sbFilesToRemove = globSync('sandbox-macos-*.sb', { cwd: targetDir });
 for (const f of sbFilesToRemove) {