Automatically detect existing codegen spec files instead of using hardcoded names

Co-authored-by: anupriya13 <[email protected]>

Author: Copilot

vnext/templates/cpp-lib/template.config.js

@@ -93,6 +93,24 @@ async function getFileMappings(config = {}, options = {}) {
       .replace('}', '') ?? crypto.randomUUID();
   const currentUser = username.sync(); // Gets the current username depending on the platform.
 
+  // Check for existing codegen spec files
+  const codegenPath = path.join(projectRoot, 'windows', projectName, 'codegen');
+  let existingSpecFiles = [];
+  let firstSpecName = null;
+  if (existsSync(codegenPath)) {
+    try {
+      const specFiles = await glob('*Spec.g.h', { cwd: codegenPath });
+      existingSpecFiles = specFiles;
+      if (specFiles.length > 0) {
+        // Extract the spec name from filename (e.g., "NativeMyModuleSpec.g.h" -> "MyModuleSpec")
+        const firstFile = specFiles[0];
+        firstSpecName = firstFile.replace(/^Native/, '').replace(/\.g\.h$/, '');
+      }
+    } catch (e) {
+      // If we can't read the codegen directory, continue with empty array
+    }
+  }
+
   const cppNugetPackages = [];
 
   const replacements = {
@@ -104,6 +122,12 @@ async function getFileMappings(config = {}, options = {}) {
     namespace: namespace,
     namespaceCpp: namespaceCpp,
 
+    // Codegen spec files information
+    existingSpecFiles: existingSpecFiles,
+    hasExistingSpecFiles: existingSpecFiles.length > 0,
+    firstSpecFile: existingSpecFiles.length > 0 ? existingSpecFiles[0] : null,
+    firstSpecName: firstSpecName,
+
     rnwVersion: rnwVersion,
     rnwPathFromProjectRoot: path
       .relative(projectRoot, rnwPath)

vnext/templates/cpp-lib/windows/MyLib/MyLib.h

@@ -6,12 +6,14 @@
 #if __has_include("codegen/Native{{ pascalName }}DataTypes.g.h")
   #include "codegen/Native{{ pascalName }}DataTypes.g.h"
 #endif
-// TODO: Update this include to match your actual TurboModule name
-// For example, if your module is named 'MyCustomModule', use:
-// #include "codegen/NativeMyCustomModuleSpec.g.h"
+{{#hasExistingSpecFiles}}
+#include "codegen/{{ firstSpecFile }}"
+{{/hasExistingSpecFiles}}
+{{^hasExistingSpecFiles}}
 #if __has_include("codegen/Native{{ pascalName }}Spec.g.h")
   #include "codegen/Native{{ pascalName }}Spec.g.h"
 #endif
+{{/hasExistingSpecFiles}}
 
 #include "NativeModules.h"
 
@@ -23,16 +25,14 @@ namespace winrt::{{ namespaceCpp }}
 REACT_MODULE({{ pascalName }})
 struct {{ pascalName }}
 {
-  // TODO: Update this to match your actual TurboModule spec name
-  // For example, if your module is named 'MyCustomModule', use:
-  // using ModuleSpec = {{ namespaceCpp }}Codegen::MyCustomModuleSpec;
-#ifdef __has_include
+{{#hasExistingSpecFiles}}
+  using ModuleSpec = {{ namespaceCpp }}Codegen::{{ firstSpecName }};
+{{/hasExistingSpecFiles}}
+{{^hasExistingSpecFiles}}
 #if __has_include("codegen/Native{{ pascalName }}Spec.g.h")
   using ModuleSpec = {{ namespaceCpp }}Codegen::{{ pascalName }}Spec;
 #endif
-#else
-  using ModuleSpec = {{ namespaceCpp }}Codegen::{{ pascalName }}Spec;
-#endif
+{{/hasExistingSpecFiles}}
 
   REACT_INIT(Initialize)
   void Initialize(React::ReactContext const &reactContext) noexcept;