chore: introduce new --native flag to Node module release process

codex-cli/bin/codex.js

@@ -1,11 +1,76 @@
 #!/usr/bin/env node
+// Unified entry point for the Codex CLI.
+/*
+ * Behavior
+ * =========
+ *   1. By default we import the JavaScript implementation located in
+ *      dist/cli.js.
+ *
+ *   2. Developers can opt-in to a pre-compiled Rust binary by setting the
+ *      environment variable CODEX_RUST to a truthy value (`1`, `true`, etc.).
+ *      When that variable is present we resolve the correct binary for the
+ *      current platform / architecture and execute it via child_process.
+ *
+ *      At the moment the npm package bundles Mac and Linux binaries, so we
+ *      fall back to the JS implementation on other platforms (though note
+ *      that Codex is not officially supported on Windows).
+ */
 
-// Unified entry point for Codex CLI on all platforms
-// Dynamically loads the compiled ESM bundle in dist/cli.js
-
+import { spawnSync } from 'child_process';
+import fs from 'fs';
 import path from 'path';
 import { fileURLToPath, pathToFileURL } from 'url';
 
+// Determine whether the user explicitly wants the Rust CLI.
+const wantsNative = (() => {
+  if (!process.env.CODEX_RUST) {return false;}
+  const val = process.env.CODEX_RUST.toLowerCase();
+  return ['1', 'true', 'yes'].includes(val);
+})();
+
+// Try native binary first (only when requested).
+
+if (wantsNative) {
+  const platform = process.platform; // 'linux', 'darwin', etc.
+  const arch = process.arch;         // 'x64', 'arm64', etc.
+
+  let targetTriple;
+  if (platform === 'linux') {
+    if (arch === 'x64')   {targetTriple = 'x86_64-unknown-linux-musl';}
+    if (arch === 'arm64') {targetTriple = 'aarch64-unknown-linux-gnu';}
+  } else if (platform === 'darwin') {
+    if (arch === 'x64')   {targetTriple = 'x86_64-apple-darwin';}
+    if (arch === 'arm64') {targetTriple = 'aarch64-apple-darwin';}
+  } else {
+    throw new Error(`Unsupported platform: ${platform} (${arch})`);
+  }
+
+  if (targetTriple) {
+    // __dirname equivalent in ESM
+    const __filename = fileURLToPath(import.meta.url);
+    const __dirname  = path.dirname(__filename);
+
+    const binaryPath = path.join(__dirname, '..', 'bin', `codex-${targetTriple}`);
+
+    if (fs.existsSync(binaryPath)) {
+      const result = spawnSync(binaryPath, process.argv.slice(2), {
+        stdio: 'inherit',
+      });
+
+      const exitCode = typeof result.status === 'number' ? result.status : 0;
+      process.exit(exitCode);
+    } else {
+      // eslint-disable-next-line no-console
+      console.warn(`[codex-cli] Native binary not found at ${binaryPath}. Falling back to JS implementation...`);
+    }
+  } else {
+    // eslint-disable-next-line no-console
+    console.warn('[codex-cli] Platform not yet supported by native binary. Falling back to JS implementation...');
+  }
+}
+
+// Fallback: execute the original JavaScript CLI.
+
 // Determine this script's directory
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = path.dirname(__filename);
@@ -21,7 +86,6 @@ const cliUrl = pathToFileURL(cliPath).href;
   } catch (err) {
     // eslint-disable-next-line no-console
     console.error(err);
-    // eslint-disable-next-line no-undef
     process.exit(1);
   }
 })();