diff --git a/package.json b/package.json
index a23fab4c22..c8f830dfe1 100644
--- a/package.json
+++ b/package.json
@@ -74,6 +74,8 @@
     "minimist": "^1.2.0",
     "object-assign": "^4.1.1",
     "platform": "^1.1.0",
+    "prettier": "^0.22.0",
+    "rimraf": "^2.6.1",
     "rollup": "^0.41.4",
     "rollup-plugin-alias": "^1.2.1",
     "rollup-plugin-babel": "^2.7.1",
@@ -83,7 +85,6 @@
     "rollup-plugin-node-resolve": "^2.0.0",
     "rollup-plugin-replace": "^1.1.1",
     "rollup-plugin-uglify": "^1.0.1",
-    "prettier": "^0.22.0",
     "run-sequence": "^1.1.4",
     "through2": "^2.0.0",
     "tmp": "~0.0.28",
diff --git a/scripts/rollup/build.js b/scripts/rollup/build.js
index f97c82939f..14218114f6 100644
--- a/scripts/rollup/build.js
+++ b/scripts/rollup/build.js
@@ -9,7 +9,8 @@ const uglify = require('rollup-plugin-uglify');
 const replace = require('rollup-plugin-replace');
 const chalk = require('chalk');
 const boxen = require('boxen');
-const { resolve } = require('path');
+const { resolve, join } = require('path');
+const rimraf = require('rimraf');
 const argv = require('minimist')(process.argv.slice(2));
 const {
   createModuleMap,
@@ -18,6 +19,8 @@ const {
   replaceInternalModules,
   getFbjsModuleAliases,
   replaceFbjsModuleAliases,
+  ignoreFBModules,
+  ignoreReactNativeModules,
 } = require('./modules');
 const {
   bundles,
@@ -150,27 +153,13 @@ function getCommonJsConfig(bundleType) {
       return {};
     case bundleTypes.RN:
       return {
-        ignore: [
-          // This imports NativeMethodsMixin, causing
-          // a circular dependency.
-          'View',
-        ]
+        ignore: ignoreReactNativeModules(),
       };
     case bundleTypes.FB:
       // Modules we don't want to inline in the bundle.
       // Force them to stay as require()s in the output.
       return {
-        ignore: [
-          // Shared mutable state.
-          // We forked an implementation of this into forwarding/.
-          'react/lib/ReactCurrentOwner',
-          'ReactCurrentOwner',
-          // At FB, we don't know them statically:
-          'ReactFeatureFlags',
-          'ReactDOMFeatureFlags',
-          // At FB, we fork this module for custom reporting flow:
-          'ReactErrorUtils',
-        ],
+        ignore: ignoreFBModules(),
       };
   }
 }
@@ -245,15 +234,19 @@ function createBundle({
   )).catch(console.error);
 }
 
-bundles.forEach(bundle => 
-  createBundle(bundle, bundleTypes.DEV).then(() => 
-    createBundle(bundle, bundleTypes.PROD).then(() =>
-      createBundle(bundle, bundleTypes.NODE).then(() => 
-        createBundle(bundle, bundleTypes.FB).then(() => 
-          createBundle(bundle, bundleTypes.RN)
+// clear the build folder
+rimraf(join('build', 'rollup'), () => {
+  bundles.forEach(bundle => 
+    createBundle(bundle, bundleTypes.DEV).then(() => 
+      createBundle(bundle, bundleTypes.PROD).then(() =>
+        createBundle(bundle, bundleTypes.NODE).then(() => 
+          createBundle(bundle, bundleTypes.FB).then(() => 
+            createBundle(bundle, bundleTypes.RN)
+          )
         )
       )
     )
-  )
-);
+  );
+});
+
 
diff --git a/scripts/rollup/modules.js b/scripts/rollup/modules.js
index e1be61d22d..ad2461cea7 100644
--- a/scripts/rollup/modules.js
+++ b/scripts/rollup/modules.js
@@ -41,33 +41,44 @@ function getExternalModules(bundleType) {
   }
 }
 
+function ignoreFBModules() {
+  return [
+    // Shared mutable state.
+    // We forked an implementation of this into forwarding/.
+    'react/lib/ReactCurrentOwner',
+    'ReactCurrentOwner',
+    // At FB, we don't know them statically:
+    'ReactFeatureFlags',
+    'ReactDOMFeatureFlags',
+    // At FB, we fork this module for custom reporting flow:
+    'ReactErrorUtils',
+  ];
+}
+
+function getCommonInternalModules() {
+  // we tell Rollup where these files are located internally, otherwise
+  // it doesn't pick them up and assumes they're external
+  return {
+      reactProdInvariant: resolve('./src/shared/utils/reactProdInvariant.js'),
+      'ReactComponentTreeHook': resolve('./src/isomorphic/hooks/ReactComponentTreeHook.js'),
+      'react/lib/checkPropTypes': resolve('./src/isomorphic/classic/types/checkPropTypes.js'),
+      'react/lib/ReactDebugCurrentFrame': resolve('./src/isomorphic/classic/element/ReactDebugCurrentFrame.js'),
+      'react/lib/ReactComponentTreeHook': resolve('./src/isomorphic/hooks/ReactComponentTreeHook.js'),
+    };
+}
+
 function getInternalModules(bundleType) {
   switch (bundleType) {
     case bundleTypes.DEV:
     case bundleTypes.PROD:
-      return {
-        // we tell Rollup where these files are located internally, otherwise
-        // it doesn't pick them up and assumes they're external
+      // for DEV and PROD UMD bundles we also need to bundle ReactCurrentOwner
+      return Object.assign(getCommonInternalModules(), {
         'ReactCurrentOwner': resolve('./src/isomorphic/classic/element/ReactCurrentOwner.js'),
         'react/lib/ReactCurrentOwner': resolve('./src/isomorphic/classic/element/ReactCurrentOwner.js'),
-        //
-        reactProdInvariant: resolve('./src/shared/utils/reactProdInvariant.js'),
-        'ReactComponentTreeHook': resolve('./src/isomorphic/hooks/ReactComponentTreeHook.js'),
-        'react/lib/checkPropTypes': resolve('./src/isomorphic/classic/types/checkPropTypes.js'),
-        'react/lib/ReactDebugCurrentFrame': resolve('./src/isomorphic/classic/element/ReactDebugCurrentFrame.js'),
-        'react/lib/ReactComponentTreeHook': resolve('./src/isomorphic/hooks/ReactComponentTreeHook.js'),
-      };    
+      });
     case bundleTypes.NODE:
     case bundleTypes.FB:
-      return {
-        // we tell Rollup where these files are located internally, otherwise
-        // it doesn't pick them up and assumes they're external
-        reactProdInvariant: resolve('./src/shared/utils/reactProdInvariant.js'),
-        'ReactComponentTreeHook': resolve('./src/isomorphic/hooks/ReactComponentTreeHook.js'),
-        'react/lib/checkPropTypes': resolve('./src/isomorphic/classic/types/checkPropTypes.js'),
-        'react/lib/ReactDebugCurrentFrame': resolve('./src/isomorphic/classic/element/ReactDebugCurrentFrame.js'),
-        'react/lib/ReactComponentTreeHook': resolve('./src/isomorphic/hooks/ReactComponentTreeHook.js'),
-      };
+      return getCommonInternalModules();
     case bundleTypes.RN:
       return {};
   }
@@ -123,6 +134,14 @@ function getFbjsModuleAliases(bundleType) {
   }
 }
 
+function ignoreReactNativeModules() {
+  return [
+    // This imports NativeMethodsMixin, causing
+    // a circular dependency.
+    'View',
+  ];
+}
+
 function replaceFbjsModuleAliases(bundleType) {
   switch (bundleType) {
     case bundleTypes.DEV:
@@ -163,4 +182,6 @@ module.exports = {
   getInternalModules,
   getFbjsModuleAliases,
   replaceFbjsModuleAliases,
+  ignoreFBModules,
+  ignoreReactNativeModules,
 };