build: add --output-transpiled-ts configuration

Author: marco-ippolito

configure.py

@@ -1169,6 +1169,12 @@
     default=False,
     help='node will load builtin modules from disk instead of from binary')
 
+parser.add_argument('--output-transpiled-ts',
+    action='store',
+    dest='output_transpiled_ts',
+    default='',
+    help='write transpiled TypeScript output to the given directory for debugging')
+
 parser.add_argument('--node-snapshot-main',
     action='store',
     dest='node_snapshot_main',
@@ -1976,6 +1982,11 @@ def configure_node(o):
     print('Warning! Loading builtin modules from disk is for development')
     o['variables']['node_builtin_modules_path'] = options.node_builtin_modules_path
 
+  if options.output_transpiled_ts:
+    o['variables']['output_transpiled_ts'] = os.path.abspath(options.output_transpiled_ts)
+  else:
+    o['variables']['output_transpiled_ts'] = ''
+
 def configure_napi(output):
   version = getnapibuildversion.get_napi_version()
   output['variables']['napi_build_version'] = version

node.gyp

@@ -6,6 +6,7 @@
     'v8_enable_31bit_smis_on_64bit_arch%': 0,
     'force_dynamic_crt%': 0,
     'node_builtin_modules_path%': '',
+    'output_transpiled_ts%': '',
     'node_core_target_name%': 'node',
     'node_enable_v8_vtunejit%': 'false',
     'node_intermediate_lib_type%': 'static_library',
@@ -457,12 +458,16 @@
     ],
     'node_mksnapshot_exec': '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)node_mksnapshot<(EXECUTABLE_SUFFIX)',
     'node_js2c_exec': '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)node_js2c<(EXECUTABLE_SUFFIX)',
+    'node_js2c_flags%': [],
     'conditions': [
       ['GENERATOR == "ninja"', {
         'node_text_start_object_path': 'src/large_pages/node_text_start.node_text_start.o'
       }, {
         'node_text_start_object_path': 'node_text_start/src/large_pages/node_text_start.o'
       }],
+      [ 'output_transpiled_ts!=""', {
+        'node_js2c_flags': [ '--output-transpiled-ts', '<(output_transpiled_ts)' ],
+      }],
       [ 'node_shared=="true"', {
         'node_target_type%': 'shared_library',
         'conditions': [
@@ -1108,6 +1113,7 @@
           ],
           'action': [
             '<(node_js2c_exec)',
+            '<@(node_js2c_flags)',
             '<@(_outputs)',
             'lib',
             'config.gypi',

tools/js2c.cc

@@ -30,6 +30,7 @@ namespace js2c {
 int Main(int argc, char* argv[]);
 
 static bool is_verbose = false;
+static std::string output_transpiled_dir;
 
 void Debug(const char* format, ...) {
   va_list arguments;
@@ -327,6 +328,25 @@ int WriteIfChanged(const Fragment& out, const std::string& dest) {
   return WriteFileSync(out, dest.c_str());
 }
 
+int MkdirpSync(const std::string& path) {
+  uv_fs_t req;
+  int r = uv_fs_mkdir(nullptr, &req, path.c_str(), 0755, nullptr);
+  uv_fs_req_cleanup(&req);
+  if (r == 0 || r == UV_EEXIST) return 0;
+  if (r == UV_ENOENT) {
+    // Parent doesn't exist, create it first.
+    size_t pos = path.find_last_of('/');
+    if (pos == std::string::npos || pos == 0) return r;
+    int pr = MkdirpSync(path.substr(0, pos));
+    if (pr != 0) return pr;
+    r = uv_fs_mkdir(nullptr, &req, path.c_str(), 0755, nullptr);
+    uv_fs_req_cleanup(&req);
+    if (r == UV_EEXIST) return 0;
+    return r;
+  }
+  return r;
+}
+
 std::string GetFileId(const std::string& filename) {
   size_t end = filename.size();
   size_t start = 0;
@@ -705,6 +725,26 @@ int AddModule(const std::string& filename,
     }
     code.assign(result.code, result.code + result.code_len);
     swc_transform_free_result(&result);
+
+    if (!output_transpiled_dir.empty()) {
+      // Write transpiled output as .js for debuggability.
+      std::string out_path = output_transpiled_dir + "/" +
+          filename.substr(0, filename.size() - kTsSuffix.size()) + ".js";
+      size_t last_slash = out_path.find_last_of('/');
+      if (last_slash != std::string::npos) {
+        int mr = MkdirpSync(out_path.substr(0, last_slash));
+        if (mr != 0) {
+          PrintUvError("mkdir", out_path.c_str(), mr);
+          return mr;
+        }
+      }
+      int wr = WriteFileSync(code, out_path.c_str());
+      if (wr != 0) {
+        PrintUvError("write", out_path.c_str(), wr);
+        return wr;
+      }
+      Debug("Wrote transpiled output to %s\n", out_path.c_str());
+    }
   }
 
   std::string file_id = GetFileId(filename);
@@ -891,6 +931,7 @@ int JS2C(const FileList& js_files,
 int PrintUsage(const char* argv0) {
   fprintf(stderr,
           "Usage: %s [--verbose] [--root /path/to/project/root] "
+          "[--output-transpiled-ts path/to/dir] "
           "path/to/output.cc path/to/directory "
           "[extra-files ...]\n",
           argv0);
@@ -915,6 +956,12 @@ int Main(int argc, char* argv[]) {
         return 1;
       }
       root_dir = argv[++i];
+    } else if (arg == "--output-transpiled-ts") {
+      if (i == argc - 1) {
+        fprintf(stderr, "--output-transpiled-ts must be followed by a path\n");
+        return 1;
+      }
+      output_transpiled_dir = argv[++i];
     } else {
       args.emplace_back(argv[i]);
     }