feat(tools): add --no-comments support to compileProtos to reduce proto file size

core/packages/tools/src/compileProtos.ts

@@ -22,6 +22,7 @@ import * as util from 'util';
 import * as pbjs from 'protobufjs-cli/pbjs';
 import * as pbts from 'protobufjs-cli/pbts';
 import * as crypto from 'crypto';
+import * as uglify from 'uglify-js';
 import {walkUp} from 'walk-up-path';
 
 export const gaxProtos = path.join(
@@ -246,6 +247,7 @@ interface CompileProtosOptions {
   esm?: boolean;
   keepCase?: boolean;
   forceNumber?: boolean;
+  noComments?: boolean;
 }
 
 /**
@@ -349,6 +351,34 @@ async function compileProtos(
   let tsResult = (await readFile(tsOutput)).toString();
   tsResult = fixDtsFile(tsResult);
   await writeFile(tsOutput, tsResult);
+
+  if (options.noComments) {
+    const uglifyOptions: uglify.MinifyOptions = {
+      output: {comments: false, beautify: false},
+      compress: false,
+      mangle: false,
+    };
+
+    const minified = uglify.minify(
+      (await readFile(jsOutput)).toString(),
+      uglifyOptions,
+    );
+    if (minified.error) {
+      throw new Error(`UglifyJS failed on ${jsOutput}: ${minified.error}`);
+    }
+    await writeFile(jsOutput, minified.code);
+
+    if (options.esm && jsOutputEsm) {
+      const esmContent = (await readFile(jsOutputEsm)).toString();
+      const minifiedEsm = uglify.minify(esmContent, uglifyOptions);
+      if (minifiedEsm.error) {
+        throw new Error(
+          `UglifyJS failed on ${jsOutputEsm}: ${minifiedEsm.error}`,
+        );
+      }
+      await writeFile(jsOutputEsm, minifiedEsm.code);
+    }
+  }
 }
 
 /**
@@ -397,6 +427,7 @@ export async function main(parameters: string[]): Promise<void> {
   let esm = false;
   let keepCase = false;
   let forceNumber = false;
+  let noComments = false;
   const directories: string[] = [];
   for (const parameter of parameters) {
     if (parameter === '--skip-json') {
@@ -415,6 +446,10 @@ export async function main(parameters: string[]): Promise<void> {
       forceNumber = true;
       continue;
     }
+    if (parameter === '--no-comments') {
+      noComments = true;
+      continue;
+    }
     // it's not an option so it's a directory
     const directory = parameter;
     directories.push(directory);
@@ -428,10 +463,17 @@ export async function main(parameters: string[]): Promise<void> {
       esm,
       keepCase,
       forceNumber,
+      noComments,
     });
   }
   const protos = await buildListOfProtos(protoJsonFiles, esm);
-  await compileProtos(rootName, protos, {skipJson, esm, keepCase, forceNumber});
+  await compileProtos(rootName, protos, {
+    skipJson,
+    esm,
+    keepCase,
+    forceNumber,
+    noComments,
+  });
 }
 
 /**

core/packages/tools/test/compileProtos.ts

@@ -103,7 +103,7 @@ describe('compileProtos tool', () => {
     assert(!js.toString().includes('require("protobufjs/minimal")'));
 
     // check that it uses proper root object; it's taken from fixtures/package.json
-    assert(js.toString().includes('$protobuf.roots._org_fake_package'));
+    assert(js.toString().includes('_org_fake_package'));
 
     const ts = await readFile(expectedTSResultFile);
     assert(ts.toString().includes('TestMessage'));
@@ -148,7 +148,7 @@ describe('compileProtos tool', () => {
     assert(!cjs.toString().includes('require("protobufjs/minimal")'));
 
     // check that it uses proper root object; it's taken from fixtures/package.json
-    assert(cjs.toString().includes('$protobuf.roots._org_fake_package'));
+    assert(cjs.toString().includes('_org_fake_package'));
 
     const js = await readFile(expectedJSResultFile);
     assert(js.toString().includes('TestMessage'));
@@ -171,7 +171,7 @@ describe('compileProtos tool', () => {
     );
 
     // check that it uses proper root object; it's taken from fixtures/package.json
-    assert(js.toString().includes('$protobuf.roots._org_fake_package'));
+    assert(js.toString().includes('_org_fake_package'));
 
     const ts = await readFile(expectedTSResultFile);
     assert(ts.toString().includes('TestMessage'));
@@ -210,7 +210,7 @@ describe('compileProtos tool', () => {
     assert(!js.toString().includes('require("protobufjs/minimal")'));
 
     // check that it uses proper root object; it's taken from fixtures/package.json
-    assert(js.toString().includes('$protobuf.roots._org_fake_package'));
+    assert(js.toString().includes('_org_fake_package'));
 
     const ts = await readFile(expectedTSResultFile);
     assert(ts.toString().includes('TestMessage'));
@@ -228,6 +228,38 @@ describe('compileProtos tool', () => {
     assert(!ts.toString().includes('import * as $protobuf from "protobufjs"'));
   });
 
+  it('compiles protos to JS without comments if --no-comments is specified', async function () {
+    this.timeout(20000);
+    await compileProtos.main(['--no-comments', 'protoLists']);
+    assert(fs.existsSync(expectedJSResultFile));
+    assert(fs.existsSync(expectedTSResultFile));
+
+    const js = await readFile(expectedJSResultFile);
+    assert(!js.toString().includes('//'));
+    assert(!js.toString().includes('/*'));
+    assert(js.toString().includes('_org_fake_package'));
+    assert(js.toString().includes('TestMessage'));
+  });
+
+  it('compiles protos to CJS and ES6 without comments if --no-comments and --esm are specified', async function () {
+    this.timeout(20000);
+    await compileProtos.main(['--no-comments', '--esm', 'esm']);
+    assert(fs.existsSync(expectedCommonJSResultFile));
+    assert(fs.existsSync(expectedJSResultFile));
+
+    const cjs = await readFile(expectedCommonJSResultFile);
+    assert(!cjs.toString().includes('//'));
+    assert(!cjs.toString().includes('/*'));
+    assert(cjs.toString().includes('_org_fake_package'));
+    assert(cjs.toString().includes('TestMessage'));
+
+    const js = await readFile(expectedJSResultFile);
+    assert(!js.toString().includes('//'));
+    assert(!js.toString().includes('/*'));
+    assert(js.toString().includes('_org_fake_package'));
+    assert(js.toString().includes('TestMessage'));
+  });
+
   it('writes an empty object if no protos are given', async () => {
     await compileProtos.main(['protoLists/empty']);
     assert(fs.existsSync(expectedJsonResultFile));