聚沙

RxJX

• https://github.com/joeyguo/blog/issues/11

Tree shaking

• rollup
• https://webpack.js.org/guides/tree-shaking/
• http://2ality.com/2015/12/webpack-tree-shaking.html
• https://www.peterbe.com/plog/advanced-closure-compiler-vs-uglifyjs2