diff --git a/js/gulpfile.js b/js/gulpfile.js
index 79095d6..fc9559f 100644
--- a/js/gulpfile.js
+++ b/js/gulpfile.js
@@ -1,25 +1,197 @@
 var gulp = require('gulp');
-var exec = require('child_process').exec;
+var execFile = require('child_process').execFile;
+var glob = require('glob');
 
-gulp.task('genproto', function (cb) {
-  exec('../src/protoc --js_out=library=testproto_libs,binary:. -I ../src -I . *.proto ../src/google/protobuf/descriptor.proto',
+function exec(command, cb) {
+  execFile('sh', ['-c', command], cb);
+}
+
+var protoc = process.env.PROTOC || '../src/protoc';
+
+var wellKnownTypes = [
+  '../src/google/protobuf/any.proto',
+  '../src/google/protobuf/api.proto',
+  '../src/google/protobuf/compiler/plugin.proto',
+  '../src/google/protobuf/descriptor.proto',
+  '../src/google/protobuf/duration.proto',
+  '../src/google/protobuf/empty.proto',
+  '../src/google/protobuf/field_mask.proto',
+  '../src/google/protobuf/source_context.proto',
+  '../src/google/protobuf/struct.proto',
+  '../src/google/protobuf/timestamp.proto',
+  '../src/google/protobuf/type.proto',
+  '../src/google/protobuf/wrappers.proto',
+];
+
+var group1Protos = [
+  'data.proto',
+  'test3.proto',
+  'test5.proto',
+  'commonjs/test6/test6.proto',
+  'test8.proto',
+  'testbinary.proto',
+  'testempty.proto',
+  'test.proto',
+];
+
+var group2Protos = [
+  'proto3_test.proto',
+  'test2.proto',
+  'test4.proto',
+  'commonjs/test7/test7.proto',
+];
+
+gulp.task('genproto_well_known_types_closure', function (cb) {
+  exec(protoc + ' --js_out=one_output_file_per_input_file,binary:. -I ../src -I . ' + wellKnownTypes.join(' '),
        function (err, stdout, stderr) {
     console.log(stdout);
     console.log(stderr);
     cb(err);
   });
-})
+});
 
-gulp.task('deps', ['genproto'], function (cb) {
-  exec('./node_modules/google-closure-library/closure/bin/build/depswriter.py *.js binary/*.js > deps.js',
+gulp.task('genproto_group1_closure', function (cb) {
+  exec(protoc + ' --js_out=library=testproto_libs1,binary:.  -I ../src -I . ' + group1Protos.join(' '),
        function (err, stdout, stderr) {
     console.log(stdout);
     console.log(stderr);
     cb(err);
   });
-})
+});
 
-gulp.task('test', ['genproto', 'deps'], function (cb) {
+gulp.task('genproto_group2_closure', function (cb) {
+  exec(protoc + ' --js_out=library=testproto_libs2,binary:.  -I ../src -I . -I commonjs ' + group2Protos.join(' '),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('genproto_well_known_types_commonjs', function (cb) {
+  exec('mkdir -p commonjs_out && ' + protoc + ' --js_out=import_style=commonjs,binary:commonjs_out -I ../src ' + wellKnownTypes.join(' '),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('genproto_group1_commonjs', function (cb) {
+  exec('mkdir -p commonjs_out && ' + protoc + ' --js_out=import_style=commonjs,binary:commonjs_out -I ../src -I commonjs -I . ' + group1Protos.join(' '),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('genproto_group2_commonjs', function (cb) {
+  exec('mkdir -p commonjs_out && ' + protoc + ' --js_out=import_style=commonjs,binary:commonjs_out -I ../src -I commonjs -I . ' + group2Protos.join(' '),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('genproto_commonjs_wellknowntypes', function (cb) {
+  exec('mkdir -p commonjs_out/node_modules/google-protobuf && ' + protoc + ' --js_out=import_style=commonjs,binary:commonjs_out/node_modules/google-protobuf -I ../src ' + wellKnownTypes.join(' '),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('genproto_wellknowntypes', function (cb) {
+  exec(protoc + ' --js_out=import_style=commonjs,binary:. -I ../src ' + wellKnownTypes.join(' '),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+function getClosureBuilderCommand(exportsFile, outputFile) {
+  return './node_modules/google-closure-library/closure/bin/build/closurebuilder.py ' +
+  '--root node_modules ' +
+  '-o compiled ' +
+  '--compiler_jar node_modules/google-closure-compiler/compiler.jar ' +
+  '-i ' + exportsFile + ' ' +
+  'map.js message.js binary/arith.js binary/constants.js binary/decoder.js ' +
+  'binary/encoder.js binary/reader.js binary/utils.js binary/writer.js ' +
+  exportsFile  + ' > ' + outputFile;
+}
+
+gulp.task('dist', ['genproto_wellknowntypes'], function (cb) {
+  // TODO(haberman): minify this more aggressively.
+  // Will require proper externs/exports.
+  exec(getClosureBuilderCommand('commonjs/export.js', 'google-protobuf.js'),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('commonjs_asserts', function (cb) {
+  exec('mkdir -p commonjs_out/test_node_modules && ' +
+       getClosureBuilderCommand(
+           'commonjs/export_asserts.js',
+           'commonjs_out/test_node_modules/closure_asserts_commonjs.js'),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('commonjs_testdeps', function (cb) {
+  exec('mkdir -p commonjs_out/test_node_modules && ' +
+       getClosureBuilderCommand(
+           'commonjs/export_testdeps.js',
+           'commonjs_out/test_node_modules/testdeps_commonjs.js'),
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('make_commonjs_out', ['dist', 'genproto_well_known_types_commonjs', 'genproto_group1_commonjs', 'genproto_group2_commonjs', 'genproto_commonjs_wellknowntypes', 'commonjs_asserts', 'commonjs_testdeps'], function (cb) {
+  // TODO(haberman): minify this more aggressively.
+  // Will require proper externs/exports.
+  var cmd = "mkdir -p commonjs_out/binary && mkdir -p commonjs_out/test_node_modules && ";
+  function addTestFile(file) {
+    cmd += 'node commonjs/rewrite_tests_for_commonjs.js < ' + file +
+           ' > commonjs_out/' + file + '&& ';
+  }
+
+  glob.sync('*_test.js').forEach(addTestFile);
+  glob.sync('binary/*_test.js').forEach(addTestFile);
+
+  exec(cmd +
+       'cp commonjs/jasmine.json commonjs_out/jasmine.json && ' +
+       'cp google-protobuf.js commonjs_out/test_node_modules && ' +
+       'cp commonjs/import_test.js commonjs_out/import_test.js',
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('deps', ['genproto_well_known_types_closure', 'genproto_group1_closure', 'genproto_group2_closure'], function (cb) {
+  exec('./node_modules/google-closure-library/closure/bin/build/depswriter.py binary/arith.js binary/constants.js binary/decoder.js binary/encoder.js binary/reader.js binary/utils.js binary/writer.js debug.js map.js message.js node_loader.js test_bootstrap.js > deps.js',
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('test_closure', ['genproto_well_known_types_closure', 'genproto_group1_closure', 'genproto_group2_closure', 'deps'], function (cb) {
   exec('JASMINE_CONFIG_PATH=jasmine.json ./node_modules/.bin/jasmine',
        function (err, stdout, stderr) {
     console.log(stdout);
@@ -27,3 +199,16 @@
     cb(err);
   });
 });
+
+gulp.task('test_commonjs', ['make_commonjs_out'], function (cb) {
+  exec('cd commonjs_out && JASMINE_CONFIG_PATH=jasmine.json NODE_PATH=test_node_modules ../node_modules/.bin/jasmine',
+       function (err, stdout, stderr) {
+    console.log(stdout);
+    console.log(stderr);
+    cb(err);
+  });
+});
+
+gulp.task('test', ['test_closure', 'test_commonjs'], function(cb) {
+  cb();
+});