🏗️🚀 Babel compile with sourcemaps

build-system/compile/compile.js

@@ -367,8 +367,8 @@ function compile(
     if (options.typeCheckOnly) {
       return gulp
         .src(srcs, {base: '.'})
+        .pipe(sourcemaps.init())
         .pipe(preClosureBabel())
-        .pipe(sourcemaps.init({loadMaps: true}))
         .pipe(gulpClosureCompile(compilerOptionsArray, checkTypesNailgunPort))
         .on('error', err => {
           handleTypeCheckError();
@@ -380,8 +380,8 @@ function compile(
       timeInfo.startTime = Date.now();
       return gulp
         .src(srcs, {base: '.'})
+        .pipe(sourcemaps.init())
         .pipe(preClosureBabel())
-        .pipe(sourcemaps.init({loadMaps: true}))
         .pipe(gulpClosureCompile(compilerOptionsArray, distNailgunPort))
         .on('error', err => {
           handleCompilerError(outputFilename);

build-system/compile/pre-closure-babel.js

@@ -16,15 +16,12 @@
 'use strict';
 
 const argv = require('minimist')(process.argv.slice(2));
-const babel = require('@babel/core');
 const conf = require('./build.conf');
 const globby = require('globby');
-const path = require('path');
+const gulpBabel = require('gulp-babel');
 const through = require('through2');
 const {BABEL_SRC_GLOBS, THIRD_PARTY_TRANSFORM_GLOBS} = require('./sources');
 
-const ROOT_DIR = path.resolve(__dirname, '../../');
-
 /**
  * Files on which to run pre-closure babel transforms.
  *
@@ -37,7 +34,7 @@ const filesToTransform = getFilesToTransform();
  *
  * @private @const {!Object<string, string>}
  */
-const cachedTransforms = {};
+const cachedTransforms = Object.create(null);
 
 /**
  * Computes the set of files on which to run pre-closure babel transforms.
@@ -60,26 +57,48 @@ function getFilesToTransform() {
  * @return {!Promise}
  */
 function preClosureBabel() {
+  const babelPlugins = conf.plugins({
+    isForTesting: !!argv.fortesting,
+    isEsmBuild: !!argv.esm,
+    isSinglePass: !!argv.single_pass,
+    isChecktypes: argv._.includes('check-types'),
+  });
+  const babel = gulpBabel({
+    plugins: babelPlugins,
+    retainLines: true,
+    compact: false,
+  });
+
   return through.obj((file, enc, next) => {
-    const cachedTransform = cachedTransforms[file.path];
+    const {relative, path} = file;
+    if (!filesToTransform.includes(relative)) {
+      return next(null, file);
+    }
+
+    const cachedTransform = cachedTransforms[path];
     if (cachedTransform) {
-      file.contents = Buffer.from(cachedTransform);
-    } else if (filesToTransform.includes(path.relative(ROOT_DIR, file.path))) {
-      const babelPlugins = conf.plugins({
-        isForTesting: !!argv.fortesting,
-        isEsmBuild: !!argv.esm,
-        isSinglePass: !!argv.single_pass,
-        isChecktypes: argv._.includes('check-types'),
-      });
-      const {code} = babel.transformFileSync(file.path, {
-        plugins: babelPlugins,
-        retainLines: true,
-        compact: false,
-      });
-      cachedTransforms[file.path] = code;
-      file.contents = Buffer.from(code);
+      return next(null, cachedTransform.clone());
+    }
+
+    let data, err;
+    function onData(d) {
+      babel.off('error', onError);
+      data = d;
     }
-    return next(null, file);
+    function onError(e) {
+      babel.off('data', onData);
+      err = e;
+    }
+    babel.once('data', onData);
+    babel.once('error', onError);
+    babel.write(file, enc, () => {
+      if (err) {
+        return next(err);
+      }
+
+      cachedTransforms[path] = data;
+      next(null, data.clone());
+    });
   });
 }
 

build-system/compile/single-pass.js

@@ -686,8 +686,8 @@ function compile(flagsArray) {
   return new Promise(function(resolve, reject) {
     gulp
       .src(srcs, {base: '.'})
+      .pipe(sourcemaps.init())
       .pipe(preClosureBabel())
-      .pipe(sourcemaps.init({loadMaps: true}))
       .pipe(gulpClosureCompile(flagsArray))
       .on('error', err => {
         handleSinglePassCompilerError();

package.json

@@ -94,6 +94,7 @@
     "gulp": "4.0.2",
     "gulp-append-prepend": "1.0.8",
     "gulp-ava": "3.0.0",
+    "gulp-babel": "8.0.0",
     "gulp-connect": "5.7.0",
     "gulp-eslint": "6.0.0",
     "gulp-eslint-if-fixed": "1.0.0",
@@ -181,8 +182,8 @@
     "typescript": "3.8.3",
     "uglifyify": "5.0.2",
     "vinyl-buffer": "1.0.1",
-    "vinyl-sourcemaps-apply": "0.2.1",
     "vinyl-source-stream": "2.0.0",
+    "vinyl-sourcemaps-apply": "0.2.1",
     "watchify": "3.11.1"
   },
   "filesize": {

yarn.lock

@@ -7831,6 +7831,16 @@ gulp-ava@3.0.0:
     resolve-cwd "^3.0.0"
     through2 "^3.0.0"
 
+gulp-babel@8.0.0:
+  version "8.0.0"
+  resolved "https://registry.yarnpkg.com/gulp-babel/-/gulp-babel-8.0.0.tgz#e0da96f4f2ec4a88dd3a3030f476e38ab2126d87"
+  integrity sha512-oomaIqDXxFkg7lbpBou/gnUkX51/Y/M2ZfSjL2hdqXTAlSWZcgZtd2o0cOH0r/eE8LWD0+Q/PsLsr2DKOoqToQ==
+  dependencies:
+    plugin-error "^1.0.1"
+    replace-ext "^1.0.0"
+    through2 "^2.0.0"
+    vinyl-sourcemaps-apply "^0.2.0"
+
 gulp-cli@^2.2.0:
   version "2.2.0"
   resolved "https://registry.yarnpkg.com/gulp-cli/-/gulp-cli-2.2.0.tgz#5533126eeb7fe415a7e3e84a297d334d5cf70ebc"