From 77ecbabf60d8f8a694a38affc55857fa6e177ffb Mon Sep 17 00:00:00 2001
From: Jordan Brant Baker <jbb@scryent.com>
Date: Mon, 7 Aug 2017 10:23:56 -0700
Subject: [PATCH] Support "env" in .babelrc files. (#8963)

---
 packages/babel-compiler/babel-compiler.js | 10 ++++++++++
 tools/tests/apps/modules/.babelrc         |  7 +++++++
 tools/tests/apps/modules/babel-env.js     | 18 ++++++++++++++++++
 tools/tests/apps/modules/package.json     |  3 +++
 4 files changed, 38 insertions(+)
 create mode 100644 tools/tests/apps/modules/.babelrc
 create mode 100644 tools/tests/apps/modules/babel-env.js

diff --git a/packages/babel-compiler/babel-compiler.js b/packages/babel-compiler/babel-compiler.js
index c10289c199..ecc2428bb6 100644
--- a/packages/babel-compiler/babel-compiler.js
+++ b/packages/babel-compiler/babel-compiler.js
@@ -300,6 +300,16 @@ BCp._inferHelper = function (
   merge(babelOptions, babelrc, "presets");
   merge(babelOptions, babelrc, "plugins");
 
+  const babelEnv = (process.env.BABEL_ENV ||
+                    process.env.NODE_ENV ||
+                    "development");
+  if (babelrc && babelrc.env && babelrc.env[babelEnv]) {
+    const env = babelrc.env[babelEnv];
+    walkBabelRC(env);
+    merge(babelOptions, env, "presets");
+    merge(babelOptions, env, "plugins");
+  }
+
   return !! (babelrc.presets ||
              babelrc.plugins);
 };
diff --git a/tools/tests/apps/modules/.babelrc b/tools/tests/apps/modules/.babelrc
new file mode 100644
index 0000000000..f5e2cf5851
--- /dev/null
+++ b/tools/tests/apps/modules/.babelrc
@@ -0,0 +1,7 @@
+{
+  "env": {
+    "development": {
+      "plugins": ["transform-do-expressions"]
+    }
+  }
+}
diff --git a/tools/tests/apps/modules/babel-env.js b/tools/tests/apps/modules/babel-env.js
new file mode 100644
index 0000000000..3cc0035b6d
--- /dev/null
+++ b/tools/tests/apps/modules/babel-env.js
@@ -0,0 +1,18 @@
+function babeltest() {
+  // use transform-do-expressions plugin to prove babel `env` subkey was loaded
+  let x = do {
+      1;
+  };
+  console.log(x)
+}
+
+/*
+  If the plugin is loaded correctly there will be no errors during the compilation of this file.
+  Without this plugin you will get the error:
+
+  W20170803-17:58:17.054(-7)? (STDERR)   var x = do {
+   W20170803-17:58:17.055(-7)? (STDERR)           ^^
+   W20170803-17:58:17.055(-7)? (STDERR) 
+   W20170803-17:58:17.055(-7)? (STDERR) SyntaxError: Unexpected token do
+*/
+
diff --git a/tools/tests/apps/modules/package.json b/tools/tests/apps/modules/package.json
index fd63fa15cb..29a8f86116 100644
--- a/tools/tests/apps/modules/package.json
+++ b/tools/tests/apps/modules/package.json
@@ -19,5 +19,8 @@
     "test": "METEOR_PROFILE=100 ../../../../meteor test --full-app --driver-package dispatch:mocha-phantomjs",
     "browser": "METEOR_PROFILE=100 ../../../../meteor test --full-app --driver-package dispatch:mocha-browser",
     "test-packages": "../../../../meteor test-packages --driver-package dispatch:mocha-phantomjs packages/modules-test-package"
+  },
+  "devDependencies": {
+    "babel-plugin-transform-do-expressions": "^6.22.0"
   }
 }