这个东西最近比较火，我也忍不住拿来研究一番
- 安装Node
brew install node
设置镜像
npm config set registry https://registry.npm.taobao.org --global
npm config set disturl https://npm.taobao.org/dist --global - 安装Yarn, Facebook提供的替代npm的工具，可以加速node模块的下载
brew install yarn
设置镜像
yarn config set registry https://registry.npm.taobao.org --global
yarn config set disturl https://npm.taobao.org/dist --global
注意不建议使用npm安装yarn,参见https://yarnpkg.com/lang/en/docs/install/#alternatives-tab
Note: Installation via npm is generally not recommended. npm is non-deterministic, packages are not signed, and npm does not perform any integrity checks other than a basic SHA1 hash, which is a security risk when installing system-wide apps.
For these reasons, it is highly recommended that you install Yarn through the installation method best suited to your operating system. - 安装React Native的命令行工具（react-native-cli）
npm install -g react-native-cli
4.安装Xcode或者Android Studio - 安装Watchman以及官方推荐的Atom插件Nuclide
brew install watchman
Nuclide只能在Atom中起一个server,运行应用还得回到命令行react-native run-xxx
预备工作完成，可以开始创建一个项目了：
react-native init HelloWorld
cd HelloWorld
react-native run-ios 或者 react-native run-android
注意项目创建后名字不能随便改，否则会出错，另外项目不要起名太高端，比如叫ReactNative，这种名字会给自己找麻烦，对，我就找了一回。
还要注意运行安卓之间必须保证有模拟器已经在运行中。
