webpack配置提取公共代码

公共代码提取功能是针对多入口文件的；

　　背景：在pageA.js和pageB.js中分别引用subPageA.js和subPageB.js

　　webpack.config.js文件：

var path = require('path')
module.exports = {
    entry:{
        pageA:'./src/pageA.js',
        pageB:'./src/pageB.js'
    },
    output: {
        filename: "[name].js",
        path:path.resolve(__dirname,'./dist')
    },
    optimization: {
        splitChunks:{
            cacheGroups: {
                vender:{
                    test:/node_modules/,
                    chunks:'initial',
                    name:'vender',
                    priority:10
                },
                utils:{
                    chunks:'initial',
                    name:'utils',
                    minSize:0
                }
            }
        }
    }
}