React安装前期工作

//验证：如下是我的安装版本，
➜  ~ node -v
v10.15.0
➜  ~ npm -v
6.4.1

//替换为国内源
sudo npm install -g cnpm --registry=https://registry.npm.taobao.org
//验证
➜  ~ cnpm -v
cnpm@6.0.0 (/usr/local/lib/node_modules/cnpm/lib/parse_argv.js)
npm@6.6.0 (/usr/local/lib/node_modules/cnpm/node_modules/npm/lib/npm.js)
node@10.15.0 (/usr/local/bin/node)
npminstall@3.20.1                 (/usr/local/lib/node_modules/cnpm/node_modules/np    minstall/lib/index.js)
prefix=/usr/local 
darwin x64 18.0.0 
registry=https://registry.npm.taobao.org

sudo cnpm install -g yarn
//验证
➜  ~ yarn -v
1.13.0

sudo npm install -g create-react-app

//注意项目名要用小写
create-react-app reactdemo