diff --git a/.babelrc b/.babelrc
index 1cdd14fd..50403603 100644
--- a/.babelrc
+++ b/.babelrc
@@ -5,6 +5,7 @@
     "transform-class-properties",
     "transform-es2015-destructuring",
     "transform-es2015-parameters",
+    "transform-es2015-spread",
     "transform-flow-strip-types",
     "transform-object-rest-spread"
   ],
diff --git a/package.json b/package.json
index 7641e0b0..c075b24c 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,7 @@
     "babel-plugin-transform-class-properties": "^6.18.0",
     "babel-plugin-transform-es2015-destructuring": "^6.23.0",
     "babel-plugin-transform-es2015-parameters": "^6.23.0",
+    "babel-plugin-transform-es2015-spread": "^6.22.0",
     "babel-plugin-transform-flow-strip-types": "^6.21.0",
     "babel-plugin-transform-object-rest-spread": "^6.20.2",
     "babel-preset-es2015-node": "^6.1.1",
diff --git a/scripts/build.js b/scripts/build.js
index 16455b23..054cbd0e 100644
--- a/scripts/build.js
+++ b/scripts/build.js
@@ -17,6 +17,8 @@
  *  node ./scripts/build.js /user/c/metro-bundler/packages/metro-abc/src/abc.js
  */
 
+'use strict';
+
 const fs = require('fs');
 const path = require('path');
 const glob = require('glob');
@@ -43,7 +45,7 @@ const babelEs5Options = Object.assign(
   {},
   babelNodeOptions,
   {presets: 'env'},
-  {plugins: [...babelNodeOptions.plugins, 'transform-runtime']}
+  {plugins: [].concat(babelNodeOptions.plugins, 'transform-runtime')}
 );
 
 const fixedWidth = str => {
@@ -87,7 +89,7 @@ function buildFile(file, silent) {
     getPackageName(file),
     'package.json'
   );
-  const {browser} = require(pkgJsonPath);
+  const browser = require(pkgJsonPath).browser;
   if (browser) {
     if (browser.indexOf(BUILD_ES5_DIR) !== 0) {
       throw new Error(
diff --git a/yarn.lock b/yarn.lock
index 2098d232..f8e28fcd 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -521,7 +521,7 @@ babel-plugin-transform-es2015-shorthand-properties@6.x, babel-plugin-transform-e
     babel-runtime "^6.22.0"
     babel-types "^6.24.1"
 
-babel-plugin-transform-es2015-spread@6.x, babel-plugin-transform-es2015-spread@^6.8.0:
+babel-plugin-transform-es2015-spread@6.x, babel-plugin-transform-es2015-spread@^6.22.0, babel-plugin-transform-es2015-spread@^6.8.0:
   version "6.22.0"
   resolved "https://registry.yarnpkg.com/babel-plugin-transform-es2015-spread/-/babel-plugin-transform-es2015-spread-6.22.0.tgz#d6d68a99f89aedc4536c81a542e8dd9f1746f8d1"
   dependencies: