webpack 打出來的 chunk.js 數量多，影響加載速度，合並配置一下即可

const webpack = require('webpack')
module.exports = {

  chainWebpack: config => {
        config.plugin('chunkPlugin').use(webpack.optimize.LimitChunkCountPlugin,[{
                maxChunks:5, // 必須大於或等於 1
                minChunkSize: 10000
            }])
    }
}

　　官方文檔地址： https://www.w3cschool.cn/doc_webpack/webpack-plugins-limit-chunk-count-plugin.html