webpack 入口参数 怎么简化？

Question

    entry: {
        app: ["event-source-polyfill", "babel-polyfill",  path.resolve(__dirname, '../ssr/entry-client.js')]
    },

"event-source-polyfill", "babel-polyfill"
这两啥作用？ 有的项目没有，怎么简化掉？