From b48ab94e16e10dac50cca6764a2c08a62d121a1a Mon Sep 17 00:00:00 2001
From: E-Liang Tan <eliang@eliangtan.com>
Date: Mon, 21 Sep 2020 17:02:24 +0800
Subject: [PATCH 1/2] Fork Babel config and reduce supported browsers

---
 .../babel.config.js                           | 33 +++++++++++++++++++
 .../webpack.config.js                         |  7 +---
 2 files changed, 34 insertions(+), 6 deletions(-)
 create mode 100644 packages/react-devtools-scheduling-profiler/babel.config.js

diff --git a/packages/react-devtools-scheduling-profiler/babel.config.js b/packages/react-devtools-scheduling-profiler/babel.config.js
new file mode 100644
index 0000000000000..ad2c37dc74f56
--- /dev/null
+++ b/packages/react-devtools-scheduling-profiler/babel.config.js
@@ -0,0 +1,33 @@
+module.exports = api => {
+  const isTest = api.env('test');
+
+  const plugins = [
+    ['@babel/plugin-transform-flow-strip-types'],
+    ['@babel/plugin-proposal-class-properties', {loose: false}],
+
+    // The plugins below fix compilation errors on Webpack 4.
+    // See: https://github.com/webpack/webpack/issues/10227
+    // TODO: Remove once we're on Webpack 5.
+    ['@babel/plugin-proposal-optional-chaining'],
+    ['@babel/plugin-proposal-nullish-coalescing-operator'],
+  ];
+  if (process.env.NODE_ENV !== 'production') {
+    plugins.push(['@babel/plugin-transform-react-jsx-source']);
+  }
+
+  return {
+    plugins,
+    presets: [
+      [
+        '@babel/preset-env',
+        {
+          targets: isTest
+            ? {node: 'current'}
+            : 'last 2 Chrome versions, last 2 Firefox versions',
+        },
+      ],
+      '@babel/preset-react',
+      '@babel/preset-flow',
+    ],
+  };
+};
diff --git a/packages/react-devtools-scheduling-profiler/webpack.config.js b/packages/react-devtools-scheduling-profiler/webpack.config.js
index b69a5d1b411ee..6cb76aa94e159 100644
--- a/packages/react-devtools-scheduling-profiler/webpack.config.js
+++ b/packages/react-devtools-scheduling-profiler/webpack.config.js
@@ -27,12 +27,7 @@ const DEVTOOLS_VERSION = getVersionString();
 const imageInlineSizeLimit = 10000;
 
 const babelOptions = {
-  configFile: resolve(
-    __dirname,
-    '..',
-    'react-devtools-shared',
-    'babel.config.js',
-  ),
+  configFile: resolve(__dirname, 'babel.config.js'),
   plugins: shouldUseDevServer
     ? [resolve(builtModulesDir, 'react-refresh/babel')]
     : [],

From 5fc7cac0794e3239f68c50d004ac0b86dc907109 Mon Sep 17 00:00:00 2001
From: E-Liang Tan <eliang@eliangtan.com>
Date: Mon, 21 Sep 2020 17:39:41 +0800
Subject: [PATCH 2/2] Revert back to original Chrome and Firefox support matrix

---
 .../babel.config.js                           | 43 ++++++++++++-------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/packages/react-devtools-scheduling-profiler/babel.config.js b/packages/react-devtools-scheduling-profiler/babel.config.js
index ad2c37dc74f56..cf0c2ea1c805a 100644
--- a/packages/react-devtools-scheduling-profiler/babel.config.js
+++ b/packages/react-devtools-scheduling-profiler/babel.config.js
@@ -1,31 +1,42 @@
+const chromeManifest = require('../react-devtools-extensions/chrome/manifest.json');
+const firefoxManifest = require('../react-devtools-extensions/firefox/manifest.json');
+
+const minChromeVersion = parseInt(chromeManifest.minimum_chrome_version, 10);
+const minFirefoxVersion = parseInt(
+  firefoxManifest.applications.gecko.strict_min_version,
+  10,
+);
+validateVersion(minChromeVersion);
+validateVersion(minFirefoxVersion);
+
+function validateVersion(version) {
+  if (version > 0 && version < 200) {
+    return;
+  }
+  throw new Error('Suspicious browser version in manifest: ' + version);
+}
+
 module.exports = api => {
   const isTest = api.env('test');
-
+  const targets = {};
+  if (isTest) {
+    targets.node = 'current';
+  } else {
+    targets.chrome = minChromeVersion.toString();
+    targets.firefox = minFirefoxVersion.toString();
+    // We won't support IE because that'll double profile import times.
+  }
   const plugins = [
     ['@babel/plugin-transform-flow-strip-types'],
     ['@babel/plugin-proposal-class-properties', {loose: false}],
-
-    // The plugins below fix compilation errors on Webpack 4.
-    // See: https://github.com/webpack/webpack/issues/10227
-    // TODO: Remove once we're on Webpack 5.
-    ['@babel/plugin-proposal-optional-chaining'],
-    ['@babel/plugin-proposal-nullish-coalescing-operator'],
   ];
   if (process.env.NODE_ENV !== 'production') {
     plugins.push(['@babel/plugin-transform-react-jsx-source']);
   }
-
   return {
     plugins,
     presets: [
-      [
-        '@babel/preset-env',
-        {
-          targets: isTest
-            ? {node: 'current'}
-            : 'last 2 Chrome versions, last 2 Firefox versions',
-        },
-      ],
+      ['@babel/preset-env', {targets}],
       '@babel/preset-react',
       '@babel/preset-flow',
     ],