[change] export ES modules by default

ES modules are the default package export. Commonjs modules are exported
from 'dist/cjs'. Modern bundlers like webpack can consume ES modules.
The addition of the `sideEffects:false` to the `package.json` helps
webpack tree-shaking modules.

package.json

@@ -5,6 +5,7 @@
   "scripts": {
     "clean": "del ./packages/*/dist",
     "compile": "yarn clean && cd packages/react-native-web && babel src --out-dir dist --ignore \"**/__tests__\"",
+    "compile:commonjs": "cd packages/react-native-web && MODULES=commonjs babel src --out-dir dist/cjs --ignore \"**/__tests__\"",
     "benchmarks": "cd packages/benchmarks && yarn build",
     "benchmarks:release": "cd packages/benchmarks && yarn release",
     "website": "cd website && yarn start",
@@ -12,11 +13,11 @@
     "flow": "flow",
     "fmt": "find packages scripts types website -name '*.js' | grep -v -E '(node_modules|dist|vendor)' | xargs yarn fmt:cmd",
     "fmt:cmd": "prettier --write",
-    "jest": "jest --config ./scripts/jest/config.js",
+    "jest": "MODULES=commonjs jest --config ./scripts/jest/config.js",
     "lint": "yarn lint:check --fix",
     "lint:check": "eslint packages scripts website",
     "precommit": "lint-staged",
-    "prerelease": "yarn test && yarn compile",
+    "prerelease": "yarn test && yarn compile && yarn compile:commonjs",
     "release": "node ./scripts/release/publish.js",
     "postrelease": "yarn website:release && yarn benchmarks:release",
     "test": "yarn flow && yarn lint:check && yarn jest --runInBand"

packages/benchmarks/webpack.config.js

@@ -32,7 +32,7 @@ module.exports = {
           options: {
             cacheDirectory: false,
             presets: babelPreset,
-            plugins: ['react-native-web', 'styled-jsx/babel']
+            plugins: ['styled-jsx/babel']
           }
         }
       }
@@ -43,5 +43,10 @@ module.exports = {
       analyzerMode: 'static',
       openAnalyzer: false
     })
-  ]
+  ],
+  resolve: {
+    alias: {
+      'react-native': 'react-native-web'
+    }
+  }
 };

packages/react-native-web/package.json

@@ -2,7 +2,9 @@
   "name": "react-native-web",
   "version": "0.6.1",
   "description": "React Native for Web",
-  "main": "dist/index.js",
+  "module": "dist/index.js",
+  "main": "dist/cjs/index.js",
+  "sideEffects": false,
   "files": [
     "dist",
     "jest",

scripts/babel/preset.js

@@ -4,6 +4,7 @@ module.exports = {
       'babel-preset-env',
       {
         loose: true,
+        modules: process.env.MODULES || false,
         exclude: ['transform-es2015-typeof-symbol'],
         targets: {
           browsers: [