feat(tools): minify proto JS files (#1435)

* feat: add minifyJs option for minifyTools

test/fixtures/echo.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright 2023 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Lots of comments we can delete in uglify
+async function main() {
+    // Showcases auto-pagination functionality.
+
+    // Let's say we have an API call that returns results grouped into pages.
+    // It accepts 4 parameters (just like gRPC stub calls do):
+    return 'SUCCESS';
+  }
+
+  main().catch(console.error);
+  // More comments
+

test/unit/minify.ts

@@ -41,11 +41,26 @@ describe('minify tool', () => {
     const objectBefore = require(echoProtoJson);
     await minify.main(testDir);
     const statAfter = await fsp.stat(echoProtoJson);
+    delete require.cache[require(echoProtoJson)];
     const objectAfter = require(echoProtoJson);
     const contentAfter = (await fsp.readFile(echoProtoJson)).toString();
     const parsedObjectAfter = JSON.parse(contentAfter);
     assert(statBefore.size > statAfter.size);
     assert.deepEqual(objectBefore, objectAfter);
     assert.deepEqual(objectBefore, parsedObjectAfter);
   });
+
+  it('minifies the proto js file', async () => {
+    const echoProtoJsFixture = path.join(fixturesDir, 'echo.js');
+    const echoProtoJs = path.join(testDir, 'echo.js');
+    await fsp.copyFile(echoProtoJsFixture, echoProtoJs);
+    const statBefore = await fsp.stat(echoProtoJs);
+    const resultBefore = require(echoProtoJs);
+    await minify.main(testDir);
+    const statAfter = await fsp.stat(echoProtoJs);
+    delete require.cache[require(echoProtoJs)];
+    const resultAfter = require(echoProtoJs);
+    assert(statBefore.size > statAfter.size);
+    assert.deepEqual(resultBefore, resultAfter);
+  });
 });

tools/minify.ts

@@ -20,13 +20,21 @@ import {promises as fsp} from 'fs';
 import * as path from 'path';
 import * as uglify from 'uglify-js';
 
-async function minifyFile(filename: string) {
+async function minifyFile(filename: string, isJs: boolean) {
   const content = (await fsp.readFile(filename)).toString();
-  const output = uglify.minify(content, {
-    expression: true,
-    compress: false, // we need to keep it valid JSON
-    output: {quote_keys: true},
-  });
+  let options;
+  if (isJs) {
+    options = {
+      expression: false,
+    };
+  } else {
+    options = {
+      expression: true,
+      compress: false, // we need to keep it valid JSON
+      output: {quote_keys: true},
+    };
+  }
+  const output = uglify.minify(content, options as uglify.MinifyOptions);
   if (output.error) {
     throw output.error;
   }
@@ -39,9 +47,14 @@ export async function main(directory?: string) {
   const jsonFiles = files.filter(file => file.match(/\.json$/));
   for (const jsonFile of jsonFiles) {
     console.log(`Minifying ${jsonFile}...`);
-    await minifyFile(path.join(buildDir, jsonFile));
+    await minifyFile(path.join(buildDir, jsonFile), false);
+  }
+  const jsFiles = files.filter(file => file.match(/\.js$/));
+  for (const jsFile of jsFiles) {
+    console.log(`Minifying ${jsFile}...`);
+    await minifyFile(path.join(buildDir, jsFile), true);
   }
-  console.log('Minified all proto JSON files successfully.');
+  console.log('Minified all proto JS and JSON files successfully.');
 }
 
 function usage() {