Made the JS generator into a plugin that builds into a binary.

BUILD

@@ -1,6 +1,6 @@
 # Protobuf JS runtime
 #
-# See also code generation logic under /src/google/protobuf/compiler/js.
+# See also code generation logic under compiler/
 
 load("@rules_pkg//:mappings.bzl", "pkg_files", "strip_prefix")
 

WORKSPACE

@@ -0,0 +1,13 @@
+
+workspace(name = "com_google_protobuf_javascript")
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "com_google_protobuf",
+    urls = ["https://github.com/protocolbuffers/protobuf/archive/refs/tags/v3.20.1.zip"],
+    strip_prefix = "protobuf-3.20.1",
+)
+
+load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
+protobuf_deps()

generator/BUILD

@@ -0,0 +1,19 @@
+
+cc_binary(
+    name = "protoc-gen-js",
+    srcs = [
+        "protoc-gen-js.cc",
+        "js_generator.cc",
+        "js_generator.h",
+        "well_known_types_embed.cc",
+        "well_known_types_embed.h",
+    ],
+    deps = [
+        #"@com_google_absl//absl/base:core_headers",
+        #"@com_google_absl//absl/container:flat_hash_map",
+        #"@com_google_absl//absl/container:flat_hash_set",
+        #"@com_google_absl//absl/strings",
+        "@com_google_protobuf//:protobuf",
+        "@com_google_protobuf//:protoc_lib",
+    ],
+)

src/google/protobuf/compiler/js/js_generator.cc → generator/js_generator.cc

@@ -29,7 +29,6 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <assert.h>
-#include <google/protobuf/compiler/js/js_generator.h>
 #include <google/protobuf/compiler/js/well_known_types_embed.h>
 #include <google/protobuf/compiler/scc.h>
 #include <google/protobuf/descriptor.h>
@@ -49,6 +48,8 @@
 #include <utility>
 #include <vector>
 
+#include "generator/js_generator.h"
+
 namespace google {
 namespace protobuf {
 namespace compiler {

generator/protoc-gen-js.cc

@@ -0,0 +1,39 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <google/protobuf/compiler/plugin.h>
+
+#include "generator/js_generator.h"
+
+int main(int argc, char** argv) {
+  std::unique_ptr<google::protobuf::compiler::CodeGenerator> generator(
+      new google::protobuf::compiler::js::Generator());
+  return google::protobuf::compiler::PluginMain(argc, argv, generator.get());
+}

gulpfile.js

@@ -6,7 +6,7 @@ function exec(command, cb) {
   execFile('sh', ['-c', command], cb);
 }
 
-var protoc = process.env.PROTOC || '../src/protoc';
+var protoc = process.env.PROTOC || 'bazel-bin/external/com_google_protobuf/protoc --plugin=protoc-gen-js=bazel-bin/generator/protoc-gen-js';
 
 var wellKnownTypes = [
   '../src/google/protobuf/any.proto',