create rollup config for processing polyfills

Author: lobsterkatie

packages/utils/rollup.polyfills.config.js

@@ -0,0 +1,28 @@
+// TODO: Swich out the sucrase hack for the real, currently-commented-out code once we switch sucrase builds on.
+
+// export default ['esm', 'cjs'].map(format => ({
+export default ['esm', 'cjs'].map(format => {
+  const config = {
+    input: '../../rollup/jsPolyfills/index.js',
+    output: {
+      // preserveModules: true,
+      dir: `jsPolyfills/${format}`,
+      format,
+      strict: false,
+    },
+  };
+  // }));
+
+  // temporary hack for testing sucrase bundles before we switch over
+  if (!process.version.startsWith('v8')) {
+    // eslint-disable-next-line no-console
+    console.log('Doing normal preserveModules in polyfill config');
+    config.output.preserveModules = true;
+  } else {
+    // eslint-disable-next-line no-console
+    console.log('Doing node 8 preserveModules in polyfill config');
+    config.preserveModules = true;
+  }
+
+  return config;
+});