Update babelrc with comments

1 files changed, 38 insertions, 0 deletions

diff --git a/.babelrc.js b/.babelrc.js
new file mode 100644
index 00000000000..27caf378b99
--- /dev/null
+++ b/.babelrc.js
@@ -0,0 +1,38 @@
+const BABEL_ENV = process.env.BABEL_ENV || process.env.NODE_ENV || null;
+
+const presets = [
+  [
+    '@babel/preset-env',
+    {
+      modules: false,
+      targets: {
+        ie: '11',
+      },
+    },
+  ],
+];
+
+// include stage 3 proposals
+const plugins = [
+  '@babel/plugin-syntax-dynamic-import',
+  '@babel/plugin-syntax-import-meta',
+  '@babel/plugin-proposal-class-properties',
+  '@babel/plugin-proposal-json-strings',
+];
+
+// add code coverage tooling if necessary
+if (BABEL_ENV === 'coverage') {
+  plugins.push([
+    'babel-plugin-istanbul',
+    {
+      exclude: ['spec/javascripts/**/*', 'app/assets/javascripts/locale/**/app.js'],
+    },
+  ]);
+}
+
+// add rewire support when running tests
+if (BABEL_ENV === 'karma' || BABEL_ENV === 'coverage') {
+  plugins.push('babel-plugin-rewire');
+}
+
+module.exports = { presets, plugins };